Apologize: Explain the situation to the teacher honestly and explain that you can't reply to the message in time because of flying, and you didn't deliberately ignore it. Express your sincerity and apology, indicating that this is an example rather than the norm.

Leave procedure: If you need to ask for leave first or submit an application for leave, provide relevant certificates or applications to prove that you really have reasonable reasons not to reply to messages during this period.

Active remedy: propose a remedy plan to make up for the inconvenience caused by not replying to the message in time. You can suggest extra study tasks, class participation or other ways to show your sincerity and efforts.

Learn a lesson: tell the teacher that you are willing to learn a lesson from this experience and make sure that similar situations will not happen again. Express your sense of responsibility for yourself and the importance you attach to your studies.

Seek understanding: try to communicate face to face with the teacher in order to better explain and communicate. Respect the teacher's decision and show that you are willing to accept the corresponding punishment or corrective measures.

The most important thing is to be honest and respectful, actively communicate with teachers, and show attention to learning and understanding of mistakes. Each school and teacher may handle it differently, so it is best to adjust the suggestions according to the specific situation.