Let's look at this in a sensible way.
AA have obviously decided that they do not want to operate a 767 on this route. Very possibly because it would make the route uneconomical and they would end up pulling it altogether. With a 757 they can maintain the route.
MAN-ORD is a long way for the 757 and so on rare occasions it has to stop off for fuel.
Would you prefer them to cancel the MAN-ORD route completely as they cannot economically justify a larger aircraft? OR perhaps keep it as it is and accept that on rare occasions it may result in a tech stop.
The other option is to transfer through LHR or a US hub which is hardly more convenient or likely to speed things up is it?
One of the reasons I like to use British Airways for long haul is that the company does have a fleet of aircraft that are fit for purpose, all year round.
That's great. Apart from they don't operate MAN-ORD!! Maybe their aircraft are all too big to make it economically viable
