Guys, when you enlist, you could do the "Manual enlistment" (bottom right corner, click that).
Then you can go through everything - nationality, bomber or fighter, squadron choice...
In the squadron choice, you can see which aircraft this unit will receive throughout it's war time;
they are listed below the aces, I think.
Those aircraft which are shown in RED, are not available yet.
You can click through the years, months or even days with arrows, to see what aircraft the unit
will have when. Also you can check that way, where the unit will be based at various times
throughout the war.
For a solid, long-lasting campaign, you should perhaps check all this out, so you know
where you are enlisting. Or when it would be time to make a transfer.
I hope this helps.