The aircraft cabin wireless network recently attracts more attentions from academia and industry. In this paper, we investigate the channel capacity in the cabin distributed multiple-input multiple-output (D-MIMO) system on the basis of measurement data collected in an MD-82 aircraft. The channel measurements are conducted at 2.4 GHz and 3.52 GHz by using a wideband MIMO channel sounder. Two different measurement scenarios, i.e., cabin aisle and cabin seat table are chosen as line-of-sight (LoS) and obstructed LoS (OLoS) environments for channel capacity studies. Two kinds of channel capacity metrics, i.e., ergodic capacity and outage capacity are characterized from the measured channel-impulse-response (CIR) data in order to explore the channel characteristics in aircraft. In each scenario, it is found that D-MIMO/distributed multipleinput single-output (D-MISO) systems can achieve significant capacity gains in comparison with single-input single-output (SISO) system. Regarding the cabin spatial position impact on capacity, measurement results further indicate that the channel capacity in cabin seat table environment decreases due to the obstruction of seat backrests. Through the comparisons of two frequency scenarios, we also find that channel capacity increases when frequency becomes larger. All these findings could provide practical references to the future applications of D-MIMO in aircraft cabin wireless systems.