As in the unit info to read, nuclear bombers are disposable weapons. 
A good regulation for this game. 
The expensive is not the bomber but the bomb, however nuke bombers without a bomb are useless, but would continue cost daily upkeep. 
That would be bad for many noobs inexperienced players. 
So CoW has a much better solution >> for every built nuclear bomb there is the nuke bomber for free with it. 
That's good for everyone. 
