1. Place the carrier on the map. Place the aircraft on the carrier. You may need to experiment a bit to discover exactly where the carrier is: as you probably know the icons on the map in the Mission Editor are not always accurate. Alternatively, use a setPos getPos command. Syntax not guaranteed.
plane1 setPos [(getPos carrier 1 select 0) + 5, getPos carrier 1 select 1, 12]
2. loon1 moveInCargo lorry1
Or if the vehicle is part of the loon's group just select "in cargo" from the Special field.