Comments earlier have made me think a little more. Let us suppose that the demand for flying to/from LHR increases over the next 5 or 10 years. Suppose also that a new runway is not built, and that there is little or no other significant runway capacity increase.
The new T2 / East is being built, and will be largely operational by about 2014 depending on what you count as operational.
Thus, in a few years time, we expect terminal capacity to significantly increase, but runway capacity to remain largely unchanged. Thus no airline can gain a competitive advantage by suddenly adding *lots* more rotations on a route without paying a heavy price for the extra slots.
A good chunk of flying at LHR is to the rest of Europe, some of it in planes of an A319 size - I'm ignoring what BMI are doing to keep slots warm as this will not last much longer.
How feasible is it for the main European airlines over a 5 year timeframe to increase the size of planes flying into LHR - maybe an A319 becomes an A320 while an A320 becomes an A321, but still remain commercially viable ? I note also BA's new use of a daily 767 to Glasgow. One immediate issue, is whether sufficient orders have been placed with Airbus and Boeing in a suitable timeframe given annual aircraft production capacity
Is this just tinkering around the edges, or is this a realistic way to squeeze a lot more passengers through Heathrow without increasing the number of flights (even if noise increases) ?