Kingfisher Airlines cancelled over 30 flights for the fourth consecutive day on Thursday severely inconveniencing passengers at airports across the country, even as some cockpit and cabin crew failed to join duty reporting sick. Over the past four days, the airline has cancelled over 120 flights maintaining they were taking some aircraft off their schedule to add business class seats in the planes.

Apart from cancelling a large number of flights due to financial constraints, there?s another trouble knocking at the airline?s doors. From Friday, Delhi International Airport (DIAL) and Hyderabad airport is putting the airline on cash-and-carry basis for airport usage as it has not cleared their dues worth R90 crore. Both these airports are run by the GMR Group.

Kingfisher had earlier give some post-dated cheques to DIAL towards dues out of which two bounced.

Aviation industry regulator Directorate General of Civil Aviation has asked the Vijay Mallya-promoted carrier to explain reasons for such mass cancellations. As per civil aviation rules (CAR), an airline has to inform the regulator before cancelling flights.

“The airline did not operate as many as 21 flights from Bangalore alone on Thursday,” said an industry source.

Kingfisher has failed to honour several payment obligations in the recent past. Public sector oil company,

HPCL last month halted fuel supply to the airline for delay in clearing R130 crore dues.

The airline has a combined debt of 7,000 crore on its books as on March 2011. With the airline finding it difficult to repay loans its lenders have restructured their debts giving much-needed respite to the carrier.

As part of the debt recast plan the banks extended the tenure of the loans and reduced interest rates. The lenders also converted 30% of their outstanding loans into preference and equity capital.

Meanwhile, pilots and engineers have started moving from Kingfisher to rival carriers as they are not getting their salaries and allowances on time. The airline has been delaying salary payment to its employees for the last many months which has become routine now. ?We are yet to get our salary for the month of October,? said an airline employee. Industry sources said dozens of Kingfisher pilots have joined rival IndiGo in the last few months.