It's infuriating me that I cannot remember the title of a series of books I read as a teenager.
I think it was a trilogy and it involves a girl being sent to live in the country with an uncle(?).
There were two or three brothers, and she ended up marrying two of them I think. The first was a pilot in WW1 and was killed doing a loop the loop, and the second was maybe a mechanic? The uncle was in a wheelchair and pretty unpleasant but hugely into horses and hunting and a big deal was made of the fact that she took so well to riding when Pilot Brother was too scared.
I vaguely recall a black velvet riding habit which I thoroughly coveted.