I’ve been saying that when travel ‘comes back’ it isn’t going to all come back right away. And though airlines will keep aircraft grounded and bring back their schedules a little bit at a time, they’re likely to bring seat capacity back faster than demand.

That’s because they have to add a plane at a time, and also because there are economies of scale in airline schedules for a hub-and-spoke carrier. They need to add flights to make existing flights work, bringing passengers from small cities, shuttling them through a hub, and connecting them onto other flights.

That means, all things equal, there should be too much capacity relative to demand and therefore cheap flights.

• Airlines will discount to bring in marginal passengers
  
• And they’ll discount to gain share shift, to pull passengers off of other airlines and onto theres

This will happen even if an airline doesn’t want to do this because there will be at least one airline that will – and once they do, they’ll get all of the business, unless others match.

However there’s one wild card that could throw a monkey wrench in the story about cheap flights as a result of limits on travel, concern about travel, and economic recession all combining to depress demand – and that’s government social distancing requirements that could be in effect in the future.

Right now no requirements are needed. There are so few people traveling that on most flights passengers can easily space out. As travel comes back, remember that airlines been adding seats to planes. American and United (but not Delta) have crammed 10 seats across in each row into their Boeing 777 aircraft.

American even continues to spend money adding seats into their domestic narrowbody aircraft at a time when they cannot spare money, and cannot fill those seats. They’re preparing for a future where passengers sit closer together, not farther apart.

But what if middle seats in economy are required to be left vacant? That would mean 2 seats of every row could not be sold. The available supply of airline seats would drop by one-third.

• Airlines would have to plan for a world with only two-thirds of seats sold at a maximum, when break-even for many carriers has been higher than that. Many flights would be money losers that couldn’t continue.

• There’d be less excess inventory to unload at low prices, meaning less pressure for fare wars.

If governments require social distancing on aircraft, that’s a future with fewer flights and higher prices. Consumers may well demand this, and airlines might respond with optional products that give them greater space for greater price while making cheaper and more dense seats available ‘in back’. But it’s also possible they wouldn’t be allowed to do so.

Of course social distancing on aircraft isn’t the only way to prevent the spread of viruses. There’s temperature checks (helpful for catching symptomatic passengers), virus testing at the airport, serology testing or documents showing you’ve had a virus already and are likely immune, among other strategies.

And come the fall we may just not be as worried about people in close proximity all the time to ban it in all cases. Once we have greater capacity to treat patients (and not overwhelm health care providers) and better treatments (to improve patient outcomes and shorten hospital stays) this may all be manageable even while we wait for a hoped-for vaccine.

Remember that after SARS, which didn’t transmit nearly as easily, many passengers in Asia continued to wear masks, but people sat beside each other without complaint (most of the time, though in rare cases complaints tended to be for.. other reasons).