Civil Aviation Minister Praful Patel talked tough, saying there was no justification for such exorbitant fares and airlines could not jack up tariffs at will. 

The ministry is gearing up to act if airlines don't start offering reasonable spot fares from next week, an issue for which CEOs of all seven airlines have been summoned to the directorate general of civil aviation on Saturday and Monday. 

For starters, the government could insist on greater transparency by airlines. It is likely to ask airlines to explain to prospective flyers exactly how many seats of a flight have been sold. 

The ministry also wants airlines to have systems in place so that people can know how much a ticket will cost if it is booked in advance, say three days, a week, or a fortnight before the travel date. This follows the government's rejection of the astronomical fares submitted by airlines for four different distance charts. The government swung into action after learning that air fares on some sectors like Delhi-Mumbai had gone as high as Rs 25,000. The DGCA issued notices asking airlines to submit a range of fares, which they did on Wednesday. 

Highly placed sources said the airlines' basic plea was that their fares keep moving up the range as an aircraft's seats keep getting sold out. They have already been asked to give route, category and period-wise fares for every month on their website so that people know the price range. 

"Airlines could be asked to depict how many seats of a flight have been sold out because of which the fares are at the level they are at. We are going to call their bluff that all seats were sold out and hence fares were at the highest level. They must tell passengers how sold out the aircraft they want to buy a seat on is and hence the fare levels being offered. There has to be complete transparency and we will do this if airlines don't do self-correction," said top sources.