May I ask if the validity period of the ID card has expired, can I fly by plane? ?

There is a period of about half a year that can be used

No, but you can apply for a temporary ID card at the public security organ at the airport, and you can pick it up on the spot.

No, you have to go to the airport police to get a temporary boarding certificate

It will not matter if it is near the expiration date or just expired, but if it is too long, you will not be able to stay in a hotel, take a plane or other means of transportation, so you should replace it with a new one as soon as possible. Or use other valid documents to travel, such as passports, military ID cards, etc. are also possible.