Does it always feel like your flight is full?

It makes sense that more people experience full flights because there are, by definition, fewer people on less-crowded flights. The other reason is that, yes, flights are indeed mostly full.

Our FRED graph above shows “load factors” for US airlines: that is, the percentage of seats sold.

The red line shows clear seasonal patterns: If you don’t like crowds, avoid flying in June and July and instead fly in January and February.

The blue line shows the same series, but removes the regular seasonal patterns. Here we can see how the load is trending within a year without having to compare with the same month in the previous years. And we see that the de-seasonalized load is fairly constant over time.

Our second FRED graph, below, shows seasonal data for domestic flights (blue line) and international flights (red line). There’s little difference between the two series, except for the period right after the pandemic. In particular, it doesn’t look like there’s much room for airlines to arbitrage between domestic and international flights during the year if the same planes could be used for both.

How these graphs were created: Search FRED for and select one of the load factor series. Click “Edit Graph” and use the “Add Line” tab to search again for the other series. Use the “Format” tab to change the settings of the second line. Proceed similarly for the second graph.

Suggested by Christian Zimmermann.