Attila the Professor said:Perhaps, perhaps, as written, that is what was intended, although I'm still rather skeptical. Glover's delivery makes quite clear to me that it's a pun on the similar sound of "thanks" and "tanks." As someone above has noted, there's only one tank used, but two or more are mentioned. The joke is the only good reason for that.
Perhaps, but I don't think so. The joke is simply better with my interpretation, ie. when the Sultan tells him all the supplies he will get, he says "You're welcome" to the Sultan instead of "Thank you", making a subtle, cheeky reference to the fact that the Sultan is giving him all those provisions as a form of thank you, and therefore does not need to be thanked in return, while also being a joke about the provisions being quite an (happily) excessive thank you.
Its quite clever wit I think, and more than a little cheeky. Donovan's a smart man, and I think that was his joke rather than a funny but still cheap "tanks!" pun.