Two more persons, including a pilot, were arrested in Ahmedabad by Delhi Police for allegedly using forged marksheets to procure licence from the country's airline regulator DGCA.
This took the total number of arrests in such cases to 11.
With this, five pilots have been arrested by Delhi Police while two others have been apprehended by Rajasthan Police in Jaipur in connection with the racket.
A senior DGCA official and three touts were also arrested in this case earlier.
"The Crime Branch team has arrested two persons from Ahmedabad. One is a pilot while another is a tout," Ashok Chand, deputy commissioner of police (crime), told PTI.
He did not provide further details.
The arrests came following investigations into a complaint filed by Directorate General of Civil Aviation that he forged marksheets to obtain a licence.
Late last week, police had arrested Abhinav Kaushik, belonging to private airline Indigo, in connection with the case.
The pilots had allegedly procured Airlines Transport Pilot Licence using fake documents.
"One has to clear three subjects -- Aviation Meteorology, Radio Aids and Instruments and Air Navigation -- to get ATPL, mandatory for becoming a Commander of a plane.
"However, these pilots failed in one or the other paper," a senior police official said.
The Delhi Police on March 26 had claimed that it had cracked the gang involved in helping pilots obtain licences using forged documents with the arrest of a senior official of DGCA and three others, including a pilot.
Pradeep Kumar (48), presently an assistant director with the DGCA, Pradeep Tyagi (35), a pilot who helped others procure fake marksheets, and his two associates Pankaj Jain (23) and Lalit Jain (34) were arrested from Delhi and Chennai last week.
Two pilots were arrested early last month.
"Tyagi is the main person behind the racket. Asatkar of Mumbai is a conduit of the gang. The pilots have paid Rs 12 lakh (Rs 1.2 million) each for the forged marksheets to get licences.
Rs 25,000 was given to Kumar by Tyagi for expediting their files," the official said.
In the wake of reports of pilots using forged marksheets, licences of 3,000 to 4,000 pilots are being scrutinised by the DGCA.