Maintaining that it has received some "interim replies" from liquor baron Vijay Mallya-owned carrier, sources in the Directorate General of Civil Aviation said it was awaiting more details as it has been found that the airline was not operating flights as per the approved winter schedule.
Mallya, meanwhile, tweeted: "Every government has gone out of the way to support airlines and connectivity. In India airlines are overtaxed and overcharged. Wonder why?"
In another tweet, he posed: "Is it Kingfisher's duty 2 fly on loss making routes when state governments tax heavily? Or should v be financially prudent n fly profitably".
Kingfisher, which has been cancelling over 30 flights each day since Monday, had yesterday cancelled 40 services across its network.
DGCA, which issued a show-cause notice to Kingfisher in this regard, has also sent similar notices to IndiGo and SpiceJet and asked them to submit their cancellation details.
"When the schedule for winter was approved, it was with immediate effect. So we took a stock of the position and on that basis, we asked them to explain," DGCA chief E K Bharat Bhushan said.
He also warned that if the airlines were found not operating the slots allotted to them, these will be given to others who are willing to operate "regardless of who it is".
As its shares crashed to a record low amid continuing debt fears, beleaguered Kingfisher sought government's intervention to help it restructure its finances.