Airlines are continuing to feel the impact of the Boeing 737 MAX groundings as American Airlines, Southwest Airlines and Fiji Airways suspend routes and Norwegian says the issue has affected passenger numbers. It still remains unclear when the troubled airliner will get back into the air as Boeing grapples with a new problem that has emerged in its bid to get regulators to accept a flight control software fix implicated in two fatal 737 MAX crashes. Carriers have been canceling flights and leasing aircraft to offset the loss of grounded  MAX aircraft and many have already indicated they will be seeking compensation from Boeing. Southwest has suspended 13 routes across the US and American dropped Dallas Fort Worth-Oakland due to the groundings. READ: Boeing sets aside $US100m for 737 MAX families Among the routes suspended by Southwest, according to The Dallas News, are Boston-Atlanta; Austin-San Francisco as well as routes from Los Angeles to Pittsburgh, Tampa and Omaha and those from Oakland to Newark, Indianapolis and Minneapolis/St Paul. The MAX groundings also contributed to a decision by Fiji Airways to suspend its Nadi-Adelaide flights from July 20. “Like any successful airline, we are constantly reviewing and optimizing scheduled routes and the aircraft used to service them, to ensure we provide the best service for our customers,’’ a spokesman told AirlineRatings. “Taking into account a number of factors, including the aircraft currently available within our fleet, we have decided to pause our direct flights to and from Adelaide. All other routes remain unchanged." Norwegian said this week traffic numbers in June were down by almost 22,000 compared to the same month last year to 3.5 million. “The total number of passengers declined slightly in June, due to the grounding of 18 Boeing 737 MAX and less charter capacity,’’ Norwegian chief executive Bjorn Kjos said. The company said it’s on-time performance in June, 70.9 percent, was also affected by the loss of the MAX aircraft and the need to use more wet-leased aircraft than normal. On the plus side, Norwegian is enjoying long-haul growth and said the delivery of a Boeing 787 Dreamliner in June meant it now had a fleet of 36 new and more fuel-efficient long-haul aircraft. International traffic in terms of revenue passenger kilometres grew by seven percent and Kjos said the number of long-haul passengers increased "considerably". “Following a period of significant expansion and investments, I’m pleased to see that the June figures show 10 percent higher unit revenue and that our growth is slowing down, in line with our strategy of moving from growth to profitability,” he said.