Frankly I'm a little surprised no one else jumped on this one already, but tally ho, I say!
1 April, 1918 was a banner day in military aviation history. On that day the first independent, co-equal Air Force came into being with the establishment of Britain's Royal Air Force. Over the last 100 years the RAF has fought and survived attempts to destroy it from within and without and remains in the forefront of air forces worldwide.
If the 100th anniversary of the RAF isn't a good reason for a campaign here on AeroScale, I don't know what is. The rules would be pretty simple, build any aeroplane flown by Britain's Royal Air Force, in any (real) colour scheme, anywhere in the world, as long as it's in RAF colours. I figure, given it's an anniversary year, the campaign would run for an entire year, but it would (of course) start on 1 April.