Crisis-hit private carrier Jet Airways has been forced to ground part of its 123-aircraft fleet following non-payment of dues to lenders, which has led to cancellation of some domestic flights, sources said. The airline however denies the cancellations are due to grounding of aircraft. The cash crunch has also pushed the airline to delay salaries for its employees and the airline, struggling with a debt of around Rs. 700 crore, needs an urgent cash infusion to keep its operations going.