Prior to the flight's departure, passengers received an email from United saying that the airline would uphold social distancing practices and block middle seating. But a UCSF medical professional found himself in a much different scenario — sat inside a completely booked, crowded cabin.

COVID-19 can travel as far as twelve feet under certain circumstances. It, too, can live on metal surfaces — an unforgiving element most of us have rested our arms on during cross-country flights — for days. So it's little wonder why airports and airplane cabins are oftentimes described by health experts as Petri dishes. And a United Airlines flight from Newark to SF Saturday proved to be just that, packed with warm bodies tighter than albacore tuna in a tin can, as observed by one UCSF scientist.

As reported by ABC7, Ethan Weiss, a UCSF cardiologist and scientist studying metabolic functions, had been in NYC tending to COVID-19 patients in the pandemic’s epicenter. After two weeks on the ground, Weiss was eager to return back to his wife, kids, and "neurotic old dog." Though, admittedly, he was anxious about leaving on his chariot-in-the-sky.

"I'm scared of getting on the airplane on Saturday," he told ABC7 just two days before his scheduled flight. "I've been taking care of COVID-19 patients for the last two weeks, and I'm more scared of getting on the airplane on Saturday than I'm walking into the hospital."

Alas, his apprehensions were realized while finding his aisle seat aboard a United-owned 737, taking to Twitter to document the ordeal.

"I guess [United Airlines] is relaxing their social distancing policy these days? Every seat full on this 737," reads one damning tweet; "This is the last time I’ll be flying again for a very long time" another tweet laments.

Weiss also published a screenshot of the United Airlines email that, before buckling his seat belt, offered hope for a much more tolerable and safe airplane ride.

It's unclear why this airplane was so booked, but ABC News reported that 25 health care workers flew home for free, so perhaps that generous gesture, ironically enough, made for a pathogenic nightmare.

United later replied with the following explanation:

We've overhauled our cleaning and safety procedures and implemented a new boarding and deplaning process to promote social distancing. Our flight to San Francisco had an additional 25 medical professionals on board who were flying for free to volunteer their time in New York - we've provided complimentary flights for more than 1,000 doctors and nurses in the past few weeks alone - and all passengers and employees were asked to wear face coverings, consistent with our new policy.

Weiss's unsettling flight comes on the heels of Wuhan announcing its first new case of COVID-19 since April 3, per Forbes.

Epidemiologists this week also continued bringing attention to the likelihood of a second wave of coronavirus crashing sometime this fall — and both contact tracing and sustained social distancing protocols will prove important in mitigating that outbreak's severity.

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Image: Unsplash via Ross Parmly