In order to meet the QoS demand of the time-sensitive information transmissions in airborne networks, a multi-priority differentiated and multi-channel MAC protocol based on the adaptive jitter mechanism is proposed in this paper. The protocol provides differentiated QoS services for different priorities by different maximum jitter stages. According to the continuous feedback of channel occupation statistics, it has the capability of traffic load self-adaptability by regulating the jitter stage transition probability. Using the M/G/1/K queuing model in the queuing stage, the 2-dimensional Markov chain model for jitters in the packet service stage, and the burst collision model in the propagation stage respectively, we derive the mathematical expressions for the performance metrics. Simulation results show that the protocol is superior to the IEEE 802.11e EDCA protocol. It can provide effective traffic differentiation, guarantee the timeliness and reliability of the highest priority, and maintain the stability of the system throughput.