LAS VEGAS (KLAS) — Spirit Airlines, the second-largest domestic carrier at Reid International Airport, continues to negotiate with Frontier Airlines on a possible merger.

Offers from Frontier, the fourth-largest airline for Las Vegas, have been favored by Spirit’s board, but rival bidder JetBlue has been getting attention with higher bids.

JetBlue is offering Spirit shareholders $33.50 in cash, or $3.6 billion. Frontier’s bid is mostly stock and only $4.13 per share in cash. At Frontier’s current stock price, the airline’s bid is worth about $22 per share, or $2.4 billion, according to an Associated Press report on Thursday.

A Spirit vote scheduled this week has now been put off until July 15 at the earliest. This marks the third time the vote has been delayed.

It’s unclear if the vote favors Frontier or JetBlue. Offers from JetBlue have been described as attempts at a hostile takeover.

The combined passenger loads of Spirit and Frontier still fall short of the leading carrier at Reid International Airport — Southwest Airlines.

Reports from last month show that Southwest carried nearly 1.6 million passengers on domestic flights in May, while Spirit nearly hit the 600,000 mark. Frontier carried 387,552 domestic passengers. JetBlue had 93,394 passengers on flights in and out of Las Vegas.

There has been speculation that the U.S. Department of Justice might not approve a merger with JetBlue because of antitrust concerns in the Northeast U.S.

In any case, passengers are unlikely to feel any affects of changes for quite some time.