A cyber squad of the air base had put him under surveillance and his emails to the woman, registered as Meena Raina, was found on the internet, Kaushal said.
IAF officials then handed him over to police, he said.
"The woman had contacted him on the social-networking media first, made friends with him and started paying him for the information," the SSP said.
The air force team kept a close watch on the online account of the Airman and found that "Sunil was in touch with a Pakistani woman on internet. He was paid for the information the accused was transmitting to the woman."