parabellum,
People might take you seriously when you read what is being replaced with the latest order.
"British Airways has today placed an order for 12 Airbus A380 and 24 Boeing 787 aircraft with options for a further seven Airbus A380s and 18 Boeing 787s."
That order is to "replace 34 of the airline's longhaul fleet and will be delivered between 2010 and 2014. The order, including options, will give the airline the ability to grow its capacity by up to four per cent per year and the flexibility to tailor its future capacity growth in line with market conditions."
Still another 37 744s to replace by around 2019, plus traffic demand between Europe and North America is predicted to have an average annual growth rate of 3.8%, Europe to Latin America of 4.6%, Europe to Africa and Middle East of 5.4%, and Europe to Asia Pacific of 6%, i.e. even on their lowest growth market, they should expect to achieve about 40% increase in demand in the next 10 years.
The aircraft BA are examining include the 787, 773ER, 748i, A380, A350XWB. The A330, A340, 767, 772, 772ER, 772LR, and 773 are not being considered.
It could be said that further longhaul orders are looking at 300+ seat aircraft, which would rule out further 787-8 & 787-9 aircraft as the existing order and options cover the 757/767 fleet with some growth.
Slots, be they terminal parking, landing, takeoff, enroute, do not have an infinite quantity. Frequency is not all the answer, the front end yield (where airlines make money) from operating a flight departing 3am somewhere and getting to the destination at 4 pm is useless.
BA fleet replacement cycle based upon 20 years of service per airframe.
BA will be announcing more orders in the future to replace eurofleet and long hauls aircraft when required.