Axis fuel transport question (no Seminole please!)

[A game]

In my current game against Seminole I have just had an issue, turn 62, I went to do my first fuel transport mission of the turn to the leading panzers and the dialogue box gives me one option, a squadron of hungarian transports... my entire fleet of german transport air is sitting within range, most of them are on 0% mileage for the turn, but they are refusing to fly?

This has never happened before and I am unsure why, could it be a shortage of fuel? How can I check that? Otherwise is there a setting somewhere I have accidentally turned the german transports onto sleep mode? Is there anything I can do as I will now have a whole lot of panzers with no gas next turn...

[Disgruntled Veteran]

Are you selecting the airfield that the transports are based? If you just select air transport without selecting a base it can often have random results. If you select the airbase that has transports and nothing happens than their is something else prohibiting it. Check morale and supply level. If morale is garbage than they might no fly. Its happened to me.