Few people (except BAA) would argue that LHR is the *best* place for an airport near London. It's biggest problem is that current flights affect several million people each and every day of the year which is why opposition is so widely spread to any form of expansion.

Many of the people using LHR are doing so in order not to go to London but to use it to go somewhere else in the world so the benefit to the UK economy isn't as high as it may appear.

Business flyers to/from London would benefit from less transit passengers as it would cut the number of flights into LHR - the proposed tax per flight rather than passenger will also encourage airlines to be more efficient in use of UK airports so you may find larger planes and less flights offered between 2 destinations especially when there are several such flights within a short period of time. This will benefit everyone whether flyer or someone living under the flightpath

It doesn't help that BA has effectively become LA (London Airways) as it doesn't offer a single international flight from anywhere except from London - so people from the "provinces" don't have much choice except to use LHR / LGW if they want to fly LA.

What would also improve flights at LHR especially would be better air traffic control - if a plane has to stack at LHR for 30 minutes wouldn't it have been better for it to travel slightly slower or leave later both of which would save the airline money and wouldn't inconvenience the passenger anymore than they do currently.

Perhaps if the Con-Dem'd government gets it's act together and builds the proposed high speed train link then Birmingham could take some of the load from LHR (and also spread the wealth further) plus it would reduce the need for domestic UK flights.