Hi everyone.. I have got a solution for you try this.
I got the same issue (not able to find Airtel network) in Qatar, I had faced this problem sometimes when I changed any sim cards. Don't panic and be patient.
Remove your sim card slot, restart your phone, and reset your mobile network settings.. Don't rush wait atleast 30 secs. Then insert your sim card slot to your mobile.. You will get Ooreedo-Airtel network if not search manually.. I have done this and it worked for me. Hope it will work everyone.