As the name implies, there is no free meal on the plane, so you have to pay for it yourself. Or buy drinks and snacks separately on the plane, but the price is more expensive.

Cheap air tickets without plane meals are generally introduced by low-cost airlines to reduce fares.

There is another exception, that is, flights with short flight time do not provide catering service. (For example, the flight time is less than one hour)

Personal suggestions for reference. If you have any questions, ask them.