Those Jazz Off the Air vinyls from Spotlite were easy to find when they came out. No idea if they are hard to find these days!
Volume 1 had one side from a Junior Jazz At The Auditorium 1946 concert with Howard McGhee, Lucky Thomson, Red Callender, etc and one side from a 1947 WNEW Saturday Night Swing Session with Fast Navarro, Bill Harris, Allern Eager, Charlie Ventura, etc..,
Volume 2 (with Art Pepper, Teddy Edwards, Wardell Gray, etc...) you have,
Volume 3 had 1944-1948 broadcasts by Benny Carter and his Orchestra. with Miles Davis, J.J. Johnson, Dexter Gordon, Lucky Thompson, Barney Bigard making short solo appearance,
Volume 4 had 1943-1946 broadcasts by Cab Calloway and his Orchestra, with Ike Quebec.
Don't know of any other volumes.