FWIW, I think folks have to make sure they can survive first before traveling. Unemployment claims remain high. Historically speaking, anything over 400,000 initial unemployment claims per week was considered a recessionary environment; i.e. 400K or more initial unemployment claims per week is a reliable recessionary indicator. Folks, we're routinely DOUBLING those numbers! While things have improved, they haven't improved enough. We could be facing a record number of evictions too. For millions of our fellow Americans, just surviving is a battle. Until that changes, people won't travel, which means the airlines won't recover.
While I'm no economist, I've always been a bit wonky that way; I was always interested in that, especially after I had economics in college. Then I knew what the CPI, GDP, etc. meant! I used to read the WSJ, Business Week, and The Economist all the time; I paid attention to business, the economy, and so on. SO! I'd say pay attention to the number of initial (i.e. first time) weekly unemployment claims. Once the number starts trending down towards 400K, things will start looking up. Once they go below 400K a week and stay there, then things will return to normal; we'll have a normal, non-recessionary, pre-COVID economy again. I wish I knew when that would happen though. If I could figure that out, I'd be a rich man! Anyway, those are my thoughts...