Weight limit | flights from Kathmandu to Lukla
The weight limit on flights to the Everest region, basically to Lukla is 15 kgs total - checked in and carry on.
This also holds true for flights to all Mountain airports on the tiny planes. Basically, phaplu, Jomsom, talcha, juphal, simikot etc
Top Tip:
If you are trekking without support, make sure you have your backpack not more than 12kgs or so. You will suffer otherwise at altitude.
If you are trekking organised and have porter support, make sure your backpack or duffel for the porter is not more than 10kgs and yours not more than five.. You will enjoy your trek that way.