Flew return journey from Miami to London Heathrow via Boston Logan. First leg uneventful on an old looking B757 on which we were served complimentary (non-alcoholic) refreshments. The second leg was on an equally old looking B767. The meals weren't as nice as the outbound flight and there was no seatback entertainment. The crew didn't seem as cheery as the outbound Chicago crew either. The plane jetted at nearly 700mph across the Atlantic at FL330, thanks to the jet stream. The gain in crossing time was lost in London as we circled for ages over Heathrow waiting for our landing slot (what a waste of fuel). I would consider flying American again once their fleet renewal is complete, but I would avoid the hassle of flying in/out of Heathrow at all costs.