Somebody asked me the other day what Mode A, and Mode B were with respect to transponders. I always thought Mode was just the "code" while C included the encoded alitiude. What is mode B?
Also, with respect to VFR cruising altitudes in the U.S., why does 14 CFR 91.159 refer to VFR cruising altitudes at the flight levels? I thought all the traffic was IFR up there.
Thanks in advance !