The event coincided with the 40th anniversary reunion of the squad organised by the Wooden Spoon children's charity of which Willie John is a regional President.
The legendary players, who were flown in from Scotland, England and Wales by Flybe, lined up to watch the unveiling and included Fran Cotton, Alan Morley, JPR Williams, Phil Bennett, Andy Irvine, Alan Old, Roger Uttley, Gareth Edwards, JJ Williams, Phil Bennett and Billy Steele.
The Irish stars comprised Willie John, Syd Millar, Mike Gibson, Fergus Slattery, Tom Grace, Jonny Moloney, Stewart McKinney and Dick Milliken.
Fred Kochak explained: "In May 1974 a squad of 34 rugby players from Ireland, Scotland, England and Wales formed the British & Irish Lions squad to travel to South Africa. They were to play against a country not beaten in 78 years.
"Their passion, commitment and determination is legendary and we are delighted to make our own unique tribute to what they achieved and the values they continue to represent.
"Dedicating an aircraft to such sporting icons is our special way of saying congratulations and a thank you to 'the Invincibles'. As she flies across the Flybe route network, we hope that 'the Invincibles' will act as an inspiration to others."
From today the Flybe Q400 OE will feature a life size image of Willie John McBride framed within a set of rugby posts. Below the cross bar are listed the 34 names of the full 1974 British & Irish Lions squad. Alongside the image is the new name of the aircraft, 'the Invincibles'.
Flybe has previously named five other aircraft to honour local sporting heroes - George Best and Mary Peters in Belfast, Kevin Keegan in Newcastle, Matt Le Tissier in Southampton and Adam Stansfield in Exeter.