I'd be saying "fleet decisions? that's what you get paid for, mate!"
In most companies, shareholders delegate management matters to the board, but set limitations - particularly in respect of large capital expenditures. If management just wanted to exercise a few options, shareholder approval would not be necessary, but a 200+ aircraft order obviously exceeds the Board's delegated powers.
EasyJet recently sought and received Board approval for their latest order, it's normal practice.
On the other hand, if the Board seek shareholder approval for a proposition with which they all agree, and present a coherent case, they would get my approval. However, as my BA shares are held by a nominee, I don't get a vote