The pandemic's biggest job winner is losing steam.

Driving the news: People who deliver packages to businesses and homes — classified as "couriers and messengers" by the Labor Department — saw the industry's biggest monthly job losses in more than 20 years in April.

Why it matters: Few industries were as supercharged as delivery over the past year. If the job drop-off lasts, it could signal a slowdown after the sector added scores of workers through the pandemic-fueled boom.

What they're saying: "Employers in the industry might be thinking that demand for delivery services won't be as strong post-pandemic as they originally thought," says Indeed Hiring Lab's Nick Bunker.

• "[T]hese services may be in demand, but not as much as was thought a few months ago."

Catch up quick: The pandemic accelerated a delivery obsession that was underway. It was already the fastest-growing job sector in the country.

• Couriers and messengers continued to add workers at an eye-popping pace, even as jobs in most other sectors dried up when shutdowns hit.

The intrigue: Even with April's disappointing employment report, no other industry is faring as well — at least when it comes to jobs.

• Courier and messenger employment is 14.3% higher now than before the pandemic hit.
• The distant second is warehousing and storage (another e-commerce winner), where employment is 5.9% higher than February 2020, per data from Brean Capital.

What to watch: Whether last month's jobs decline was a blip.