Below is a list of jobs and occupations that are frequent timepasses on icarus. These range from actual jobs to hobbies and some things in between. They're arranged in 4 Categories: Arts & Crafts, Law & Order, Free Time & Entertainment and Household Help. 
This list is not complete but gives a general feel of what you might expect when on Icarus.  

Arts & Crafts
-Animal Healing/Husbandry
Animal Healing/Husbandry is taken very seriously as animals, especially tamed ones, need to be guarded from outside prdators. When an animal is injured, even if it is wild, it is taken in by the Animal Healer Specialists for appropriate care. When the animal has recuperated it is given back to it’s keeper or released back into the wild.
-Animal Keeping
It isn't uncommon for farmers to have some animals as well. Since both horses and cows weren't salvagable from the Hyantis, farmers make due with Camels and Nurks, a kind of long-furred big, horned goat found almost everywhere on Icarus.

Archers defend the cities and castles in time of attack (for instance by Nex Necii) but also entertain people by showing their skills at fairs and circusses. They can shoot arrows blindfolded and paired archers train to shoot arrows accurately from the back of a flying drak.
Creativity has always been at the core of the human mind. People draw, paint and create with the materials they find around them. People with exceptional skills are even paid for their works. 
Forger of utensils, blades and shields. They also maintain older equipment. 
-Candle Making
There is no electrical lighting on Icarus. As such candles are a great source of additional light in the evening. There are also oil lamps. 
The creating of musical scores. Musical notation is identical to that of Earth. 
A farmer is a farmer is a farmer. Farmers live on the outskirts of villages. They provide food for the villages as well as for the Castles. In return, Castles provide protection from Mobs-when they can-for the villagers. A farmer is paid highly for their crops as they are in the most danger from attacks by Mobs. Usually a farmer has a Fairy Drak or two to send to Castles, but Fairy Draks don’t always make it to castles and back in time as they are too small and their electronic brain-waves aren’t strong enough to be picked up by the Portals. Farmers risk life and limb to provide food for Castles and they are darned proud of themselves.
The people who build houses. These craftsman don't only work with stone, but also with wood and metal. 
-Chief Mason
Acts like an architect in that this is the person who  leads the build and decides the layout. 
People wishing to become Medics spend several years learning from Chief Medics the different muscles, bones, and scientific names for each part of the body. They also will learn the names of everything inside a human body. Occasionally, the apprentices will learn by on-the-job training when they have become good enough. They run errands for the Chief Medics and are always at his beck and call.
-Chief Medic
The Chief Medic has completed his training and has enough training to be capable of doing his job without supervision. He can also take on students (medics) and teach them human anatomy and what they need to cure certain diseases.
-Message Carrier
Not all messages are delivered by Draks. Local messages are usually delivered by message carriers. Sometimes these message carriers take on longer trips, usually when they have access to a bicorn or camel. 
-Playing an Instrument
Many people on Icarus play a kind of instrument. The most prevalent are pipes, flutes, drums and stringed instruments like the guitar and ukulele. Metal is not commonly used in instruments though some people have paid to get a metal instrument. 
People who play exceptionally well sometimes join a travelling fair or circus. 

History needs to be recorded and stock needs to be accounted for. Scribes usually work in larger guild halls and libraries to keep note of what's happening. 
Everybody can sing, but some are more skilled in it than others. Those can study with other professional singers and perform in circusses and on fairs and holidays. 
Woodsman with a knack for animal rearing sometimes tame wild creatures and sell them for a profit. 
The men and women who venture out in the forest. They serve various roles. They check for fire hazards, avalanche or flood signs. They hunt certain animals when the population gets too large and make sure dwindling populations get the time to balance out. 
Creates wooden utensils and sometimes art pieces. 

Law & Order
There is usually one Sheriff and a few deputies in each town. They keep riots to a minimum as well as keeping violence at a low. People who defy the laws set by the Sheriff are put in prison for a month. People who murder are put on trial and if found guilty can spend up to fifteen years in prison or be put to death.
Deputies aid the local Sheriff to keep the peace. As a deputy you can make promotion when the Sheriff quits his job (or dies). The one with the most qualifications is usually awarded the job, though at times exceptions are made.
The person who jusges at the trials. This is an elected seat.
-Peace Keepers
People who patrol the small villages and solve disputes before they escalate. 
-Bounty Hunters
Every now and then someone tries to evade his/her punishment. Bounty hunters make a living catching these people. They also try to locate mob hideouts. 
If a prisoner escapes they usually go into the woods and join the Mobs…if they can find them.
Mobs are groups of outlaws who wreak havoc on the outer-village regions. They steal what they can and kill everyone who was a witness, or old enough to remember. Anyone below the age of three they take with them to train as members of their Mob. Anyone over that age they slaughter. Mobs train their ‘apprentices’ to take any amount of pain or injury. They make them walk across hot embers, hot metals, and heated broken glass. They never wear shoes and are forced to wear skin-tight shinobi’s (Ninja Uniforms) but are extremely flexible with the human body. They are also forced to wear masks for their entire life because if they are seen by anyone they will be killed by the Mob because they become a risk factor to the Mob. They know how to do Karate and Fencing (usually with two swords) extremely well. They are forced to be able to climb trees without using ropes or anything else but their own two hands and feet and are trained to move from one tree to another when an area is thick with trees. They each carry a knife on each ankle and a sword at each hip.
Trained by the first person to ever brake away from a Mob, these Ninjas protect villagers with their lives. They swear honor, protection, and respect. The Ninjas are trained much like the Mob members are and also use two swords for fighting. They have, like the Mob, two knifes at each ankle and two swords at each hip. They too wear the skin-tight clothing, but each Ninja Band has it’s own colors that stand out as being Ninja members and not Mob Members.

Free Time & Entertainment
-Board Games
People enjoy their games wherever they end up. Some of Earth's Board Games thus survived the crash on Icarus and are still played by the inhabitats of both Castles, Villages and Cities. However since communities lay rather seperated from each other, local changes can be observed in those board games, bringing variety to the old games.
-Apprentice Fencer
An Apprentice Fencer takes a class with at least fourteen other Apprentices under one Chief Fencer. An Apprentice Fencer can range from many ages but if one shows a liking for the sport at an early age, they are prompted to join as soon as possible (usu. They will not be accepted until the age of ten as this will make it so they don’t have ten-year-old or younger Chief Fencers running around). If the Apprentice shows extraordinary abilities, the Chief Fencer may ask the Apprentice if s/he would like to be specially trained on the Chief Fencers time or he/she will recommend another advanced Chief Fencer to the Apprentice. This is a special opportunity and is rarely turned down. When an Apprentice is chosen to be instructed alone, s/he must promise to stay under instruction until their training is complete. When the Apprentice(s) has(have) finished training, s/he can now move on to their future career.
-Apprentice-Chief Fencer
An Apprentice-Chief Fencers are literally the ‘middle-people’. Usually after four to five years of being an Apprentice Fencer, s/he will become an Apprentice-Chief Fencer. Sometimes this happens sooner if the Apprentice Fencer has shown extraordinary skills at Fencing and was taken under special charge of a Chief Fencer. The Apprentice-Chief Fencer now has the choice to train on their own time with a Chief Fencer as they basically have completed their training and only need a little more. An Apprentice-Chief Fencer usually helps a Chief Fencer with his/her classes or simply watches the Chief Fencer instruct his/her classes. At around the ages of sixteen to eighteen, if the Apprentice-Chief Fencer has shown that they can handle teaching classes, has great patience and/or has improved their abilities, they then are graduated to a Chief Fencer.
-Chief Fencer
A Chief Fencer instructs up to fifteen Apprentice Fencers. S/he should be very patient and willing to go over things with their Apprentices several times over. Every-so-often a Chief Fencer will spot an above-average apprentice and train him/her alone and on his/her own time if the Apprentice is so-willing. Often, Chief Fencers will recommend that his/her Apprentices take Karate as well as this helps them with balance, maneuverability, flexibility and concentration. A Chief Fencer is responsible for all of his/her Apprentices and therefore must watch over them carefully to make sure that, when dueling, neither Apprentice is seriously injured. A few minor injuries do, of course, occur from time-to-time, but the Chief Fencer makes sure that the Apprentice is well taken care of and receives immediate medical attention. If an Apprentice is caught fooling around or being boisterous during training, they will immediately be subject to a two-day period of isolation. This is so they learn to be careful as Fencing is a very dangerous sport, even with the armor on. If the Apprentice is caught being rambunctious again, the Chief Fencer may subject the Apprentice to an even longer isolation if s/he thinks it is so vital for the Apprentice.
Travelling groups with jesters, clowns, trained animals and sometimes also a troupe of actors who perform plays. Each circus is different. 
Aside Mountain Climbing, Hiking is a favourite passtime of village youths. Exploring the surroundings of their villages, running through the forests and making forts in the hills they are sometimes joined by older men and women who stick to the roads and keep an eye out ;)
-Ice Skating
A passtime enjoyed in the High North and Low South of Icarus where the lakes and ponds freeze over at certain times of the years despite the gentil seasons on the planet.
Jousting takes place between two riders and their reptilian mounts. To be able to be qualified for jousting, a person must take at least two years of training along with safety classes. This prevents serious injuries. A jouster must always wear armor with the crest of the Castle/Village they are from painted on the right and left shoulder plates. It is an expensive sport, but if you are the winner, you are handsomely rewarded. There are first, second and third place trophies that await the winner and runner-ups as well as a certificate of achievement. The rest walk away with ribbons and certificates that state their involvement in the tournament(s).
-Air Jousting
Air Jousting takes place between two Knights and their Draks. Extreme safety precautions are taken during Air Jousting Practices. Large nets are stretched across a vast area usually in grassy valleys. Long bungee-type cords are attached to a harness. The harness is buckled around a rider’s shoulders, waist, and legs. Then the other end of the bungee is secured to a harness around the Drak. The rider wears thick padding under the harness and a padded helmet, and each jouster has a long jousting pole. At the end of each jousting pole there is a lot of padding in order to keep from seriously injuring the other rider.
Juggling is a cheap passtime. Regional competitions are usually held. 
Karate is taken by Fencers, Competitions and for self-defense. There are several hundred Karate Masters all over. There are enough of them that some make the choice to take on only one Apprentice. An Apprentice Fencer will usually spend, if encouraged by the Chief Fencer, every other day learning Karate for five years. If the Apprentice Fencer chooses to continue their training, then they are usually taken on by a lone Karate Master. An Apprentice devoted entirely to Karate can spend up to twenty years (and are usually encouraged to start training at five years of age) learning from a Master and they usually go right to a Karate Master and train alone with the Master.
-Mountain Climbing
Mountain Climbers are often loners. Sometimes, when they meet fellow Mountain Climbers, they form groups and climb together and sometimes stay together as ‘buds’ until the day they stop climbing. When one first starts out, they may ask for the guidance of an experienced Mountain Climber and usually climb smaller and less dangerous mountains. That is all that is really known about Mountain Climbers. The only ones who know more are the Mountain Climbers themselves.
With the absence of horses on Icarus, races are held with Camels and a local kind of six-limbed reptile that are just called 'Racer' for their main purpose. These races are usually held on the outskirts of villages or cities, on dirt road tracks that run in a rough loop.
-Drak Racing
Similar to normal Races, Drak Races are all about speed and stamina. Short and longer races in a straight line over the continent are held to pass time in the Castles. Contrary to the land-based Racers, Draks use their wings to stay ahead, flying at great speeds to 

Household Help
-(Castle) Cook
The person who cooks in a castle. Usually has a lot of organisational talents as well. From breakfast, lunch to diner and dessert, they know recipes to make verything from scratch. Some of the richer households also have a person in charge of cooking but they may have other duties as well. 
-(Castle) Kitchen Maid/Manservant
The kitchen maids/manservants take on the job of cleaning the kitchen and the adjoining rooms. They can also be sent for groceries and help the cook with the preparations. 
-(Castle) Maid)/Manservant
They clean and air out the rooms, wash the linens and clothes and are generally there to do whatever work is asked of them. Some work to maintain the tools and gardens while others carry buckets of water. They light the fireplaces and candles in the evening.
Every household of note might employ a cleric to keep track of the finances. 
People with skills in combat or sports can be hired to safeguard people of note.