Shake Shack has tripled its planned number of stores to 1,500, as the fast-casual chain’s popularity grows. The restaurant also recently partnered with Delta Air Lines to serve its burgers to passengers.

Shake Shack has raised its target for company-operated restaurants in America to “at least" 1,500 in the long-term, the company revealed.

The burger chain is targeting 1,500 company-owned units by enhancing leadership, boosting operations and entering new markets, executives said at ICR.