Houston to San Antonio

What the Data Says About IAH to SAT

The Houston to San Antonio corridor (IAH → SAT) covers roughly 191 miles and is served by 12 carriers, based on Bureau of Transportation Statistics reporting. Across 13,003 flights in the dataset, this route posts a 81.1% on-time rate with an average delay of 70.3 minutes when flights run late. Over the most recent 24 months of BTS data, 4,529 flights were recorded on this pairing — 78 cancelled (1.7%) and 4 diverted (0.1%). Those baseline metrics tell you what to expect before you book.

Having 12 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 13,003 total flights analyzed, the 81.1% on-time figure is statistically meaningful rather than a small-sample fluke. The 70.3-minute average delay applies only to flights that actually ran late, so it is not the average wait across all departures — the majority of flights on this route depart on time under the BTS definition of a delay (15+ minutes past schedule).

Looking at recent months, Sep 2025 posted the best performance on this corridor at 87% on-time, while Jul 2024 came in at 59% on-time — a 29-point gap between best and worst recent month. For travelers evaluating the IAH to SAT route, the combination of a 81.1% on-time rate, 70.3-minute average delay, 1.7% recent cancellation rate, and 12 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.