The polycount recommended for aircraft is between 1 and 2 thousand but the battleships are up to 35000 so if your over the 2 dont worry too much - will only be a problem if you have loads on the screen at one time
Yes aircraft can be added - the floatplanes are an addition
http://web.telia.com/~u18230645/ Sergbuto did them so he may be the best to help you
Maybe one aircraft to do is the Spitfire which can double up as the Seafire for carrier use as you tend to see a lot more fighters than bombers - well I do anyway
Good luck in your model
