A lot of the same people who say "just don't drop the fighter hangars" will be the first ones up & posting on 200 about how stupid you were to try & take the field with the hangars up...or will cry because someone got a cap in place before they could get up, or on your own side complaining; "now how are we gonna defend the field when we take it?" When what they really mean is "now I can't vulch the uppers" B.T.W. a CAP is what the guys over the field call it...the guys on the tarmac call it vulching.
Man someone spray some air freshener cause sombody just took a dump.

1) People who want the fighter hangers up, don't want the field captured because they want the enemy to be able to up and fight between the two fields all night.
2) Vulchers are like a disease, useless, skilless and lame. Most people don't vulch after they finnally learn to do more than fly down a runway and die. Most of the vets that vulch are do it cause they can't get a good score fighting. This is much of the reason score means nothing.
3) A cap is in concert with a base capture. If it is not you are just a lowly vulcher. See #2.
4) People who drop the field first are just admitting that they can not get coordinated enough to have the cap, town killers and goons on the base in time and in force to take it. So to buy their skilless and riskless selves more time they level the field and worry about the town and goon later.
What the #4 people don't realize is that, 9 out of 10 times, destroying the field is only going to gaurantee an unsuccessful base capture. Pooface is dead on and all the rest are just people's explanations for having too few countrymen to do the job, too little skill and no guts.
The big problem is that most base capture guys in #4 camp don't want to fight, that is why the first thing they do is eliminate any chance for the enemy to fight back. It kinda seems counter to why people would play this game.
Personally I am here for the fight and long fought out battles for bases are what I enjoy after I have had my share of furballing.
When the hangers go down I leave that fight all together as most do and then the FH bombers are left there with their rods in their hands and usually get whiped, wondering "A duh, why didn't we get that field?" I'll tell you why, cause you wasted all your resources on the field instead of what get you the capture, the Town.
Don't listen to the furball dweebs, and don't listen to the strategy folks. Try everything out for yourself, decide which type of gameplay you like and then have fun doing it.
Funny most of us have been telling him to do both and have fun.
As for your initial question - as has been stated, the game is "won" when one country is reduced to three airfields.
For me the game is won, when I have been fighting my arse off all night in the same kick arse furball and I log exhuasted and eager to do that again. Unfortunately if it aint Fester, Oz or Donut it doesn't happen.