Driving me Crazy

[AFV]

Turn 1 as the German. I had a very successful air campaign- 6,475 Soviet aircraft destroyed, followed by dropping supplies to the leading edge armored units.
Turn 2- I cannot get any transports to drop supplies. Period. Same for turn 3.
Air Doctrine- set to 0% to fly
Air bases are not in swamps
Range is set to unlimited for all planes
I have tried running the missions from a base with transports, to not selecting any specific bases. Tried on units far out and also units very close.

Its the air war in WITE, which means its extremely likely the ultimate answer will just point to me being an idiot. Regardless, does anyone have any ideas on what I am doing wrong?

[56ajax]

Have to be within 5 hexes of a rail head?

[AFV]

Is that a thing really, just for transports? It is quite possible they are not. I will look in Chris's manual for that.

[AFV]

Thanks Ajax
16.3.5.1. Air Transport of Supply
Supplies and fuel can be airdropped (F9) to units by transport and level bomber air group units and this mission can be
escorted by fighter air group units (5.3.9). There’s a limit of two air transport missions per hex and they may only be flown
by air groups that are located on airbases within 5 MPs of a supply source (rail net).