Sir Keith commanded RAF squadrons during 1940 Luftwaffe attacks
A campaign to put a statue of RAF hero Sir Keith Park in London's Trafalgar Square will continue, despite the mayor admitting it would be "difficult".
Campaigners want to honour Sir Keith with a permanent statue on the square's fourth plinth, backed by his native New Zealand and mayor Boris Johnson.
But the mayor said complex planning issues made it "difficult to secure this location on an ongoing basis".
A campaign spokesman said: "It will be difficult but not impossible."
Sir Keith commanded RAF squadrons which defended London and the South East from Luftwaffe attacks in 1940.
The Sir Keith Park Memorial Campaign wants a statue of him erected on the plinth which is currently reserved for a revolving programme of modern art.
'Brave and distinguished'
In a written answer to London Assembly member Jennette Arnold, Mr Johnson said Sir Keith's "brave and distinguished service" should be honoured "with a permanent statue in the heart of central London".
But he added: "There are also outstanding commitments to exhibit contemporary sculpture on the fourth plinth.
"I recognise that this revolving programme has proved very popular with the public and I welcome the important contribution it has made in shaping public debate about contemporary art."
Mr Johnson said he would talk to campaigners to find "the best option available for them in view of these circumstances".
Sir Keith Park Memorial Campaign director Karl McCartney said: "We never thought it was going to be an easy ride, but it is all systems go as far as we are concerned."
The group is in talks with Westminster City Council next week.
The council's director of planning and city development, Rosemarie MacQueen, said: "We are taking their proposal seriously as Sir Keith played a crucial role in the Battle of Britain."
Next week New Zealand's defence minister Phil Goff is due to deliver a letter to Mr Johnson signed by all New Zealand party leaders in support of the campaign.