I have nursed through practically every take off and landing I've been on in the last year, and my son has been on 7 trips. I buy him a seat for my own comfort (he's a big baby) but since he's the right age to be a lap child I figure that he's ok in my lap. Since the baby and the passengers around me are all more comfortable if he's nursing instead of screaming, I go ahead and do it. Once he's asleep he sits in his seat, strapped in and safe.