Firstly, let me apologise for the lack of information in my first post. To be honest, I don't remember posting it, was uber drunk.
The thought as it appeared in my head during sober times was;
Example:
Bish capture Rook large field. They have to bomb fighter hangers and VH to take field. At the time of taking the field, everything is down, bar the buff hangers. Ack, Dar, FH's, VH - proably some moron also took down Troops, Ord and Fuel. There is nothing on the field available.
The level of the captured field should reflect it's condition at the time of capture. So, with the example above, having only 4 Hangers total still up, only 4 ammenities should be available to the capturers.
1) Ack - which pops automatically anyway
2) VH
3 +4) 2x FH's
This will make the field essentially a Small Airfield.
My timings are noticable off. So lets say that the Bish hold this field for an hour. After that hour, if the field is linked to a friendly supply route and is fully up (for that hour), the field evolves into a medium field. The process can be helped along by supply bringing vehicles (Goon/M3). A fully operational small field can be upgraded by 8 sets of field supplies.
2 hours or 16 supplies evolves the field to Medium and 3 hours or 24 sets of supplies eveolves the field to Large (but the field has to remain fully up for that hour).
If a field is taken by a suprise attack and only the town is dropped, the field status remains the same (large remains large, etc.) and all amienities are available to the capturer.
And this is the craziest idea ever as it probably means recoding the entire game.