British Airways has launched a long awaited competition for new long-haul aircraft to replace its current 114-strong fleet of Boeings.
Arch rivals Airbus and Boeing, engine manufacturers Engine Alliance, General Electric and Derby-based Rolls-Royce, along with other key component suppliers, have all been invited to bid.
The competition - called a request for proposal (RFP) - is the first stage of a lengthy process before the airline makes a decision on the growth of the fleet and replacement for the next decade.
BA chief executive Willie Walsh said: "For the past four years, we have grown capacity by using our aircraft more efficiently.
"In order to continue to grow our long-haul business we now need additional long-haul aircraft. We remain committed to generating an economic return for our shareholders."
He stressed that the launch of the competition highlighted the need for BA to address its £2.1 billion pension deficit.
"It is a major blocker to growth and investment in our business but I am confident we will resolve it," he said.
"With a combination of firm orders and options, we are planning for both growth and fleet replacement into the next decade."
He said environmental performance would be one of the key criteria in BA's choice, ensuring greater fuel efficiency, reduced noise and emissions.
"The first aircraft to be replaced are the 20 Boeing 747s and 14 Boeing 767s, which will be around 25 years old," he added.
Europe's third-biggest airline, which wants to take delivery of the first new planes by early 2009, said it was too soon to say how many planes it would acquire, although analysts said the bill would be at least £3.7 billion.
An early order date could benefit Boeing, since Airbus is still struggling to launch its proposed new mid-sized A350 model - now set for 2012 deliveries at the earliest - and will still be working through a series of delayed orders for the first of its A380 superjumbos.
But analysts expect BA's requirements will be allotted on a winner-take-all basis.
"We believe it is unlikely the order will be split between the two aircraft manufacturers, given the operating and maintenance simplicity of operating a single fleet," UBS analysts said in a client note.
Mr Walsh expects proposals from the planemakers by the end of the year.
Analysts also expect that BA, already stretched as it tries to resolve its pension deficit, will go further into debt to fund the acquisitions.
"Their debt is obviously going to go up quite significantly," said Exane BNP analyst Nick van den Brul.
BA said it expected to place the orders next year and that the aircraft it was considering were Airbus's A330, A350 and A380s and Boeing's 787 Dreamliner, 777 and 747-8s. List prices for the aircraft range from $160 million to $316 million (£86 million to £170 million).
A BA spokesman said the airline will not consider the four-engine A340 model because it did not suit its needs.
Boeing expects to begin deliveries of the 787 in 2008, but heavy demand could make it tough for BA to find aircraft for several years unless other carriers are willing to swap their delivery slots with BA.
BA announced earlier this year it had secured delivery slots for ten 777s by 2010.