Started as a joke to sailing, but the more I thought about it it sounds like something that could be made to work 
Gnome Gliders as level 1: You glide short-distance
- Woodcutting for wood
- Fletching and/or crafting for making aircraft parts from wood
You can eventually make an aircraft and propel it.
Fuel:
- Herb makes sense to make fuel
- Low level fuel = low level herbs; scalable
- Can involve that lab in Rimmington more (and tie-in quests for fuel research with that guy)
- PoH Lab
- More herb recipes for fuel, or could tie-in a more general science-y skill like Invention
- Coal and superheat spell sound useful here too
- Mages being eco-friendly come up with using Runes for fuel instead of Coal
Airport:
- Construction → PoH → Player-owned Airport!
- Hire butlers for ATC
- Something like that RS3 Bonfire quest where there’s other Gelinor airports (and a quest to build em)
- Throne of Misc like where you can earn income and assign aircraft to do stuff
- Can have something like using helicopters being cheaper to start trips but longer delay between rewards vs a jet requiring more fuel and ATC (lowering rewards) but being faster
- You build 5 aircraft; Canfis needs coal from Seers → one aircraft for the job is 8hrs (or 6 if jet), you send the plane off and 6-8 hrs you have a reward; you have 4 aircraft left to send on jobs
- You build your own aircraft (until mages figure out how to flatpack em), but can trade aircraft parts with players (presumably monsters aren’t dropping aircraft parts )
Flying Grand Exchange:
- The GE now floats on a hovering rock powered by mages
- Players have to fly to it with appropriate skill level and aircraft
- Flying GE needs maintained: All GE sales taxed (or lifted with daily fuel submission quests; mages use it for fallback or something if eco-questioned )
- Flying GE can change hourly (unstable air?) and change flying requirements too (you gotta plan to go to the GE
)
Flight paths:
- Like WoW
- Higher flying levels allows shortcuts between paths (like agility); also benefits PoH airport with higher rewards/less delay
- Some destinations and paths have fuel type requirement (can’t fly over Entrana with a coal-burning craft, only pure Cosmic Rune dust approved in this airspace )
Other players:
- Fly to other players sky house!
- If player A has high-level sky house/reqs, player B flying to it must meet flying level req
- PoH skyhouse can also be a high-level party ship (with tiers so low-level blimp too)
- Trading between other player PoH airports (AoE2 trading cart style)
Air drop:
- You can air drop supplies from your bank (food, pots)
- Butler from PoH airport can deliver X items to your player tile on request (above ground; airspace fuel reqs, aircraft type, flying level for shortcuts, and fuel type/reserve determine how quick you’re supplied and how-often)
- Butler can also take items from you to bank (like BoB RS3?; scaling costs/amount/etc based on level)
- High-level can request a volatile mix drop on enemies also with the above time references (can nuke a dragon in the wild )
- Players in wild are fair-game too (Ice Barrage from above )
- New inventory item: Anti-air (nullifies another player’s aerial attack; like RS3 Demonic Skull you hold it while in the wild as potential protection; has charges)
- New Prayer: Anti-air (cancels out another player’s air drop capabilities for 1min+stacking if they’re within your 3x3 tile range)
- Air recovery: Request butler pick-up anywhere above-ground to PoH (similar 20min cooldown), with scaling wilderness levels needing butlers requiring high rep (below minigame); not affected by tele-block but also not usable while under anti-air Prayer effects from another player
Deathmatch Minigame:
- Fly to a new instance of the wilderness (something RFD style)
- Instanced/safe death
- Small sections of the wild would be used at random (like a lvl 1-14 square from Edgeville or around green dragon pit)
- Maps slightly modified with more small houses/cover
- Something like Castle Wars, but the only objective is to kill the most
- Loadouts (melee, ranged, magic, customs)
- Deathmatch rules (quick respawn, FFA, 20min matches; damage/HP reworked)
- CoD-style killstreaks (air drops of better weapons/HP, predator missiles, area fire, bio-cloud areas for poison ticks like Zulrah)
- Mages created a remote that gives you UX interfaces for killstreaks
- Rewards: Fuel, combat XP, reputation (higher rep used to hire better butlers for PoH, or spent in R&D for better PoH airport rewards/times)
- Also a casual way to get people in the wild and trying new stuff
- Gungame: Magic/Ranged/Melee
- Gungame Magic: Everyone starts with Wind Strike; 1 kill → Water Strike → (several kills/spells later) Fire Wave, Barrage (requiring a few kills to progress)
- Mario Kart-like random powerups/modifiers; you pick up something, it gives you 1-shot Dharok’s for 20 secs (or invincibility); Relic of Vengeance (Ice): Upon your death you launch an Ice Barrage on your tile affecting anyone in it
- Music could be different-pitch classic wilderness tracks (like WoW does with higher-pitched classic music in pet battles)
Other:
- I recall a Gnome airport light thing with a quest; it sounds like Gnomes already have the basics down so this could add a lot of Gnome quest opportunities
- Quests can also introduce cool real-world air/flight knowledge
- PvP with PoH Airports could be something like Forge of Empires with opt-in