well I kinda got the idea from civ ctp, in it the aircraft have to be refuled, and they could be refuled in citys, at airports, or on aircraft carriors
mabe, you could have it so if you land it neer an active frendly building it would automaticly refuel (from people comming out with hoses or somthing and refueling it, of corse that anamation dosnt have to be)
they would refuel quicker at a airbase though
and mabe, for extended missions, there could be a support fueling vec, it would be able to manufacture the fuel out of the air, but because it is a ground vec, the system can be alot heavyer and alot less efficent, alloing you to build them as soon as you can build the fuel VTOLs, the vec would most likely have heavy armor, and mabe a small defence wep (although it would be highly encuraged to for it to have escort vecs) and when it dies, it would make a explosion simmiler to a starflair (because its full of high grade jet fuel)
that way, your jets can perform extended sorties away from your coloney, eathor perfoming bombing runs, or transporting large groups of vecs (the vecs load while the VTOL is refueling)
mabe have a script you could write kinda like the one with the cargo truck, so they constantly patrol that area, just tell it where to load, where the destonation is, and where to refuel, and they would fly that route untill you tell them to stop
another 2 cents lol