Allegiant Air, acknowledging reliability issues with several of its six Boeing 757-200 aircraft, says it has formulated a wide-ranging plan to correct them that includes overhauling and upgrading components in the pneumatic system of its 757 fleet.

The airline identified that system in particular as causing many of the mechanical issues that necessitated recent flight delays. The Las Vegas-based low-cost carrier also is adjusting its flight schedule to provide extra spare aircraft coverage on peak flying days, among other measures.

“We are keenly aware of the impact our delays have caused for our customers and are working diligently to improve our operation,” the low-cost carrier says.

The 757 is a new fleet type for Allegiant, which previously operated only MD-80 aircraft; it currently is using them primarily for Hawaii services. But the new services generated some negative publicity last month when mechanical issues with three of the aircraft delayed the departure of more than 1,000 passengers, some for as long as two days.