The WW1 kites are definitely much fun to fly and fight with.
As Skylla said, we do have a WW1 zone to the east of our training mission so you can do your fights without being jumped by the WW2 guys all the time.
The WW1 part of training mission features two airfields close to Stalingrad, with about 5 minutes flight time to each other or to the AI dogfight zone respectively.
In the AI dogfight zone you meet one or two (randomly, sometimes just one, sometimes two) opponents of random types with random skills, so it never gets boring.
You've got all kites available (currently two on each side: Spad XIII, Sopwith Camel, Fokker Dr.1 and Pfalz D.IIIa) with all available modifications.
What else there is to say about Flying Circus?
Well... the fighting style is significantly different to WW2.
Time after time, we expect to see all ROF content being ported to FC, but it will surely take a few years to do so.
Probably the most important step would be to have a dedicated WW1 map and some ground objects.
At the moment you're essentially flying a canvas plane in a WW2 scenario, giving you little other options than to shoot down other canvas planes.
You definitely get to know so when you try to kill enemy ground objects with your bomblets or peashooters, or if you happen to get within enemy AAA's range.
Mike