Allah Allah..... weird.
If you have closed the Airport...you would say "OK, land your plane in Saudi Arabia, we are gonna search the plane if you are really carrying humanitarian aid, we will let you land in Yemen". If plane is not complying, you would fire some warning shots and repeat your orders again. If the plane is still not complying you would shot it down.
Saudi's have the US backing when It comes Iran... so they would face no problems in UN, like Israel... so why they didn't shoot the plane.... very weird.