Airline investors are feeling bullish following strong results from Delta Air Lines, meaning stocks including JetBlue Airways (JBLU -3.62%) are enjoying a tailwind. Shares of JetBlue were up 10% as of 1 p.m. ET following Delta's quarterly results.

A JetBlue plane on the tarmac.

Image source: JetBlue.

Delta delivers, others take notice

Airlines tend to be cyclical, performing well when times are good and consumers have money to spend on vacations. Shares have been under pressure this year due to concerns that higher inflation and tariff-related uncertainty would lead to less demand.

On Thursday, Delta kicked off airline earnings season by beating expectations and reinstating full-year guidance ahead of the consensus estimate.

Investors are betting that if Delta is seeing strong demand, the rest of the industry is too. Though JetBlue will not report its results for weeks, investors are bidding the shares up on anticipation that strong demand will boost earnings.

Is JetBlue a buy?

Although airline stocks tend to move together, investors should be aware there are significant differences between Delta and JetBlue. Delta is part of a "big four" that control about 80% of the domestic industry, leaving smaller companies like JetBlue scrambling to soak up demand where they can.

JetBlue has been a lot less profitable than Delta in recent quarters and faces a significant debt burden.

Shares of JetBlue are down nearly 40% year to date even with Thursday's rally. The outlook for the company is at least slightly better today than it was yesterday, but investors should remain cautious around this stock.