Delta Air Lines has been proposed as a sponsor to rehabilitate Skymark Airlines Inc by the bankrupt Japanese carrier's biggest creditor - a plan that challenges a separate proposal that has put forward ANA Holdings as a sponsor.

If the move is approved by a majority of creditors, it could help Delta use Tokyo's Haneda airport as a transit hub for passengers coming off its flights from Los Angeles. Currently, Delta's connecting opportunities are limited because it has no alliance partner in Japan.

Skymark's creditors are slated to vote on the rival plans by an August 5 meeting of debt holders. Both plans would likely result in the winning sponsor taking a stake of under 20 percent in the discount airline.

Airline leasing firm Intrepid Aviation, Skymark's biggest creditor, said it had conducted a thorough process to identify the strongest sponsor candidate.

"(We) focused on airlines that have a strong presence and operations in Japan combined with long-term commitment to Skymark's successful rehabilitation," Intrepid said in a statement.

The rival plan promoting ANA, Japan's biggest carrier, as sponsor is backed by Skymark and domestic private equity firm Integral Corp.

For ANA, gaining a foothold in Skymark would give it access to additional landing rights at Haneda, where along with its affiliates, it already holds more than half the 486 slots, helping cement its dominance of domestic air travel in Japan.

Intrepid, Skymark's biggest creditor, holds 38.1 percent of Skymark's debt, followed by European aircraft maker Airbus Group with 28.9 percent and jet engine maker Rolls-Royce Holdings with 15.7 percent.

Skymark holds 36 landing slots at Tokyo's Haneda Airport, which connects to cities throughout Japan and which many travelers prefer to Narita International Airport because it is closer to central Tokyo.

Skymark Airlines ran into financial trouble after an ambitious expansion that included buying Airbus A380 jumbo jets. It filed for rehabilitation proceedings in late January.