我国飞机编号是在字母后加几个数字？

答案解析：在中国，民用飞机的注册编号通常由一个汉字（代表中国的“中国”或“民航”） followed by a series of letters and numbers. The specific format can vary, but a common format for commercial aircraft is something like “B-XXXX”, where “B” stands for China (assigned by the International Civil Aviation Organization, ICAO), and “XXXX” represents a sequence of four numbers. Hence, the answer to the question is 4, indicating that there are four digits following the letter in the aircraft registration number. Military aircraft may have different numbering schemes, but for the context of this question, the focus is on the typical civilian aircraft registration format.