Kills in bombers are recorded on the web site, but seeing as you get no points for kills in a bomber they do not appear on the score boards in the game.
But kills of Gv in bombers do appear on the score board in game, even though they too do not give you anything for score. That's the great oddity that has never been explained
And realgood, no kills are lost. Your kills of planes do indeed show up on the web scores, as Fugitive said
And on the web statistic pages all kills of yours do always appear, no matter what you were in or what you did kill.