Air:
Flying into Manchester from the U.S. is a viable alternative to flying into Heathrow or Gatwick. This may be preferable to those travelers keen on going to Scotland or, like myself, expecting to attend a Manchester United match. It's quite possible that you'll find the occasional special fare to Manchester that'll be cheaper than London, though generally London is slightly less expensive. Manchester's airport is serviced by a number of major international airlines. In our case, we flew in from Chicago on American on a Sunday (for the same price as flying into London), which worked very well for us, since our first Man U game was Tuesday.

Manchester's airport is not located in the city proper. You will be required to take a train into town. Don't waste your rail pass on this train ride, unless you plan to travel extensively by rail on the same day. It only costs about 4 quid to ride into town. There are friendly people working at the information desk if you need assistance. Don't be afraid to ask for help. Note: there are almost no trash cans in the airport, so get rid of your rubbish, stale gum, etc. on the plane.