Delta Airlines reports second quarter results on Thursday. One thing investors will be scrutinizing is a relatively new service from the carrier: parcel delivery. The offering, spun up last year, could help Delta cash in on the growth of e-commerce.

But it comes with some risks.

Transporting cargo is nothing new for passenger airlines.

“It honestly kind of takes me back to the origins of the airline industry,” said Dan Bubb, a professor of aviation at the University of Nevada, Las Vegas. “The airline industry actually began by transporting mail.”

In fact, in those early days, the line between cargo and passenger was a little blurry.

“At one time, actually, passengers, believe it or not, had to sit on bags of mail. That was your seat,” Bubb said.

Even after airlines added real seats for people, many still earned extra cash by filling spare cargo space with packages, said airline consultant Robert Mann.

“With thousands of flights a day major network carriers, there's a lot of cargo capacity that goes unutilized,” Mann said.

But Delta’s new program is about more than filling empty space.

“Well, the uniqueness of it is, first off, it’s door-to-door,” said Mann.

Delta is the only major carrier offering that service. And that could be attractive to shipping customers who don’t want to bother getting their packages to the airport.

“These days going to the airport is a whole lot more difficult than it used to be,” Mann said. “There's a whole lot more, you know, agita and cost and time involved.”

While most of Delta’s operations involve airports and airplanes, Delta and other carriers actually manage some door-to-door logistics already, said Vijay Pandiarajan, a business professor at the University of Michigan.

“Delta already has great experience delivering, for example, delayed baggage,” Pandiarajan said.

So, the new service, which uses third party delivery firms for the last mile, builds on that capacity. But the strategy has some limitations.

“There are a lot of remote places where you don’t have Delta flying in,” Pandiarajan said.

Erie, Pennsylvania, or Lincoln, Nebraska, for example, both cities where Delta has ceased service. Meaning that last mile delivery, could be a last hundred-mile delivery. Established players like Fedex, UPS and Amazon have that down to science.

“They’ve got warehouses everywhere,” said Bubb. “They’ve got trucks driving all night.”

Bubb said the timing of shipments could also be uncertain, because Delta might not know how much extra cargo space a flight is going to have.

If they are transporting cargo on the passenger flights, the bags get priority, and human organs, anything of a critical nature gets priority,” said Bubb.

Plus, passenger flights can, and do, get delayed.

Correction (July 9 2025): A previous version of this story misspelled the name of Erie, Pennsylvania.