I have flown about 11 round trips this year, by my count, all beginning and ending in Florida. I can certainly count on my fingers (likely on just one hand) the total number of empty seats on the 25+ flights, combined (a few trips had layovers).
More often, people on standby were turned way and I turned down offers to be bumped for credits to take later flights. United, Delta, JetBlue, Spirit, and Hawaiian Airlines are the ones I have flown on this year. 99+% full.
Maybe flying to/from Indiana is different. I have gone from Ft. Lauderdale/Miami/West Palm to/from Atlanta, Boston, DC, New York, Philadelphia, Charlotte, Dallas, Seattle, San Francisco, Chicago, and Honolulu.