If things go perfectly, U.S. airline seating capacity this July will return almost to the level it was at in July 2019, when demand in that pre-Covid-19 environment propelled U.S. carriers to one of their busiest months in history.

Alas, things are very unlikely to go perfectly, especially in international air travel markets.

Despite new indications of countries potentially opening their borders to fully vaccinated American travelers at various times this summer, most countries remain, for now, mostly closed to U.S. travelers unwilling to go through long, expensive and frustrating quarantine protocols upon arrival in those countries.

 And even when those countries do open up to U.S. visitors – and the U.S. reciprocates by allowing visitors from those same nations – you can expect that lots of travelers will remain skittish about venturing abroad with the pandemic not yet over. And even those who are very eager to travel internationally still are likely to be required to jump through more hoops than normal to do so.

As it stands today, U.S. carriers expect to offer only about 2% fewer departing seats in July in the domestic market than they offered in July 2019. That’s based on the schedules they’ve already filed and seats that already are available for sale.

And they currently have about 11.1 million departing seats on international flights scheduled in July. That’s about 3 million fewer international seats than were offered in July 2019, but way, way up from their near non-existent seat offerings in international markets a year ago.

Still, those 11.1 million July departing international seats currently for sale are about 5.1 million more departing seats than U.S. airlines had on offer for this month – May. The chances of international travel demand nearly doubling in just two short months while the pandemic continues, even at a slowing pace, aren’t high.

And making the challenge even more difficult is the high probability that U.S. carriers will reduce significantly the number of international seats they ultimately will fly in July. The number of international seats they actually will fly this month vis-à-vis the 5.1 million they started out trying to sell is as yet unknown. But in every month since last summer, when airlines first began predicting a recovery of demand from the initial collapse of demand in the wake of the Covid-19 pandemic, they’ve started out by scheduling lots more capacity – domestic and international – for the month only to cancel millions of seats by the middle of the month, once they recognized how far demand was going to fall short of their original, hopeful projections. And that process is likely to be repeated again this month, in June, in July and perhaps for many more months.

For example, according to from OAG, which tracks airline capacity, sales and other data globally, US. carriers began the year with 449 million departing seats on domestic routes being offered through the first six months. But in each of the first four months of this year they had to cancel thousands of scheduled domestic flights containing millions of seats because demand simply didn’t materialize to justify than many flights and seats. Currently, their total offered domestic seats for the first six months of this year is down to 348 million, with the rest of May and all of June still to go. Thus, though demand is rising now, thanks to increased vaccination rates and lots of people who are in desperate need of an emotional fix for their Travel Jones, it’s likely that those same carriers will end up cancelling more flights in May and June. It’s possible that they’ll end up actually flying only around 300 million domestic seats in the first six months of this year. That would be a full third fewer than they originally were offering when the year began.

So, if we apply that same percentage – a one-third decline – to international travel demand, the 11.1 million seats that OAG says U.S. carriers originally offered for sale in July would come in closer to 7.4 million. But because international travel is both more expensive and not even yet certain to be allowed, OAG suggests the total number of seats that’ll be available on U.S. carriers’ international flights could be well short of even that. 

OAG also notes that in July US carriers currently plan to serve only 1,117 foreign airport, 267 fewer foreign airports than they served in July 2019 (but way up from the 532 foreign airports they served in July 2020).

Currently a number of European nations are working on plans to begin allowing entry to fully vaccinated Americans – and perhaps those from a number of other nations. But the details, dates and testing protocols are not all set yet, which means Americans who need to plan their summer vacations in May in order to schedule the rest of their busy summer around those dates, might not be able to commit to travel to, say the United Kingdom or Europe and will have to opt for some other, easier-to-plan destination. Chances are, such travel planners will opt for a domestic destination instead, or perhaps a trip to Mexico, where U.S. travelers face few restrictions either upon their arrival in Mexico or their return home. In fact, the lack of restrictions explains why the U.S.-Mexico travel market, always one of the biggest travel markets for U.S. citizens, now ranks, at least temporarily, as the world’s busiest international air travel market.

Meanwhile, many consumers continue to harbor significant worries about traveling during the pandemic. Others are having their summers truncated by a late end to the school year as many districts around the nation keep going deep into June in order to make-up for lost school weeks during the year. And most nations are only now beginning to consider when and how to go about re-opening their borders to visitors and are risking missing the key travel planning window for many people who otherwise want to visit there.

Thus, it’s increasingly clear that U.S. carriers’ optimism about carrying lots more international travelers this summer is beginning to fade now, even before the summer travel season officially begins in four weeks.