The authority first extended the date till Aug 31, then changed it to Sep 19 and now Oct 31.

"For the third time in the last one-and-half months, the AAI has deferred till October last the effective date of implementation of its order, reducing the runway length of the airport," said an official of the state government dealing with civil aviation.

The runway had become unsafe for the operation of large aircraft after the AAI re-notified its length due to the presence of trees near it, the official said.

Patna airport director Arvind Dubey said the AAI decided to extend its deadline to implement the revised runway distances at the airport.

According to government officials, the state government has removed most of the obstructions to implement the AAI order for safety of the airport.

The AAI, on the recommendation of the Directorate General of Civil Aviation, had re-notified the airport's runway length after the Bihar government refused to cut or prune trees near it early August.

Pruning and cutting of trees was vital for the safe landing and takeoff of the aircraft, said an airport official.

According to forest department officials, hundreds of trees have been pruned or cut, besides removal of advertising hoardings and street lights near the airport.