Load factor measures how much of an airline's passenger carrying capacity is used.
Shares of the Long Island City, New York-based airline were up slightly to $19.14.
Traffic in May increased 5.7% to $4.59 million revenue passenger miles from May 2018. Capacity increased 5.4% to 5.34 billion available seat miles. Revenue passengers increased 1.4% to 3.69 million, while departures declined 1.2% to 31,073.
On-time performance, or domestic flights arriving with 14 minutes of schedule, was 77.6%.
JetBlue said that it expects second-quarter revenue per available seat mile to range between 2% and 4%. The airline's shares rose on Tuesday after Citi analyst Kevin Crissey upgraded his rating on JetBlue to buy from neutral.
Crissey wrote that "with fuel prices now well below levels when guidance was provided, RASM, or revenue per available seat mile, can be weak or even negative, and JetBlue can still exceed consensus."
Wall Street is looking for roughly $2.30 in 2020 earnings per share, while the company has set a target of $2.50 to $3. In April, JetBlue reported first-quarter earnings and revenue that glided past analysts' expectations amid an increase in passenger traffic and contained per-passenger costs.
Net income for the first quarter came in at $42 million, or 14 cents a share, compared with $90 million, or 28 cents a share, in the comparable year-earlier period. Analysts polled by FactSet had been expecting per-share earnings of 12 cents. On an adjusted basis, the company earned 16 cents a share.