TLDR: the ability to cancel a flight or jump from the flight within the first few minutes.
If you are just a few minutes into a flight (say less than 5 minutes for this suggestion but 2-3 minutes or a percentage of the flight, etc works too) and realize that you shouldn't have flown yet for some reason, we could have the option to abort the flight, particularly with the private jet/airstrip but could be modified to work with the other flight options as well.
If I board a flight to Argentina for example and less than 3 minutes in (or whatever time), I wanted to cancel the flight, it would be cool to be able to abort the flight and the plane would turn around and maybe take 5 more minutes to get turned around and landed back. That would be better than the time it takes of flying the whole way there and back.
Or potentially have the option to jump but incurring some health damage (potential here for another item similar to a parachute, or to change the current parachute to something else, and to be able to buy and use that item to minimize or eliminate the health damage incurred, or possibly as a requirement to jump)....
Just a thought, I'm sure all of us have boarded a flight just to realize you needed to buy/sell items, deposit money/items into vault/faction armory, faction organized crime is about to start, needed to pay rent or send money/items, use energy/nerve, etc first but still have to complete that flight even though you realized it as you pushed the button and there was plenty of time to stop the plane before it even got off the ground lol.