it was generally not allowed to bring your own microwave onto an airplane as part of your carry-on or checked baggage. Microwaves are considered large electrical appliances and are not permitted as standard carry-on items due to safety and security concerns.
Carry-on baggage typically has restrictions on the size and weight of items, and a microwave would exceed those limitations. Additionally, microwaves contain electrical components and can potentially interfere with the aircraft's systems, which is why they are not allowed in the cabin.
If you have a specific need for a microwave at your destination, it is best to arrange for one to be available there, such as in your accommodation or at the place you'll be staying.
Keep in mind that airline regulations and policies may change over time, so I recommend checking with your airline or the relevant aviation authorities for the most up-to-date information regarding what is allowed on board an aircraft.