Less than a week after 9/11, even the US government was trying to get people to go back to the usual socio-economic activities and was not widely hostile to cross-border travel. I was on US carriers on 9/10 and on 9/11, and I was flying back into the US within 7 days after 9/11. And with the exception of a handful of days, I was able to continue to fly in the weeks and months after 9/11 with no substantial risk of additional big surprises ruining my travel ability. [The biggest disruption for me was that some US long-haul routes were cancelled and that DCA was removed as an option for some weeks, meaning I had to deal with the hassle of getting to NY in other ways or to use IAD or BWI.]

This time is very different than 9/11.

The scope and scale of concern about cross-border travel and travel in general is way greater now with this virus situation than in the weeks and months after 9/11. And the economic damage from this virus situation is way more extreme and intense than 9/11 was. Governments have shown that they can and will change the rules on rather short notice. These are ingredients for a very uncertain, very slow and very uneven recovery in the market for air travel .... even with the unprecedented amounts of fiscal and monetary stimulus being deployed at this time.