刷飞机

刷飞机 means rapidly sending the 飞机 (airplane) virtual gift in a livestream. On 抖音, 快手, and 虎牙 the airplane is one of the higher-tier paid gifts (often hundreds to thousands of RMB each). 刷 here is the 'spam / send a stream of' verb - also seen in 刷火箭 (spam rockets, even pricier), 刷礼物 (spam gifts in general). Big spenders earn 榜一大哥 (top-donor) status.

Internet / livestream-economy slang. Wouldn't appear in formal writing, but is universally understood by anyone who's spent time on 抖音直播 or game-streaming platforms.