These airlines have canceled and delayed the most flights so far in 2022

• The 17 biggest US airlines canceled 3.20% of domestic flights between January and June.
• During the same time last year, they only canceled 1.58%, DOT data shows.

Travelers have been forced to make last-minute changes to their vacations this summer as airlines canceled and delayed thousands of flights.

Understaffing, technical problems, extreme weather, and soaring demand for travel have all pushed airlines to the limits. Overall, the US' 17 biggest airlines canceled more than 3% of domestic operations between January and June, compared to 1.58% during the same time period last year, according to data from the US Department of Transportation.

Republic Airways, a regional carrier that operates some services as American Eagle, Delta Connection, and United Express, canceled the most flights in the first half of the year at 10,270, or 6% of its schedule, according to the DoT data. In June alone, it canceled 8.8% of its operations.

Between January and June 2021, in comparison, Republic Airways canceled just 1.43% of its operations.

Republic Airways was followed by JetBlue Airways, which canceled 5.39% of its operations in the first half of 2022, and Mesa Airlines, which canceled 4.48%. Allegiant Air came close behind with a 4.43% cancellation rate.

The DoT data just takes into account cancellations that were made within a week of the flight's scheduled departure date, and not flights that were canceled further in advance than that.

Here's the percentage of operations each airline canceled between January and June 2022, listed from worst to best:

1. Republic Airways – 6.00%
2. JetBlue Airways – 5.39%
3. Mesa Airlines – 4.48%
4. Allegiant Air – 4.43%
5. PSA Airlines – 4.13%
6. American Airlines – 3.88%
7. Endeavor Air – 3.84%
8. Spirit Airlines – 3.76%
9. Alaska Airlines – 3.33%
10. Frontier Airlines – 3.21%
11. Envoy Air – 2.96%
12. Southwest Airlines – 2.66%
13. United Airlines – 2.44%
14. Skywest Airlines – 2.36%
15. Delta Air Lines – 2.20%
16. Horizon Air – 1.98%
17. Hawaiian Airlines – 0.97%

Almost a quarter of all US flights were late in the first half of 2022

Overall, 75.89% of domestic flights operated by US airlines arrived "on time" between January and June, classed as flights that arrived within 15 minutes of their scheduled time, according to the DoT data.

During the same time period in 2021, 84.29% of flights arrived on time. The DoT takes into all scheduled flights, and therefore classes flights that are diverted or canceled as flights that didn't arrive on time.

Allegiant Air flights were most likely to be disrupted, with 38.37% arriving at least 15 minutes late or being canceled or diverted, the data shows. This figure is even higher when just June is taken into account, with just 59% of the airline's domestic flights arriving on time that month, per the DoT data.

Allegiant Air was followed by JetBlue Airways, which had 62.08% of its scheduled flights arrive on time in the first half of 2022, and Frontier Airlines, at 64.50%.

Across all airlines, afternoon and evening flights were the most likely to be delayed. The data shows that more than 80% of flights scheduled to depart from airports between 6:00 a.m. and 9:59 a.m. local time then arrived on time, compared to less than 60% of flights scheduled to depart between 7:00 p.m. and 10:59 p.m. local time.

Some airports are much more prone to flight delays, too. Of the US' 30 largest airports, Chicago's Midway International Airport ranked worst for on-time departures, followed by Newark Liberty International Airport, and Baltimore/Washington International Airport.

Here's the percentage of flights operated by each airline that arrived within 15 minutes of their scheduled arrival time between January and June 2022, listed from lowest to highest:

1. Allegiant Air – 61.63%
2. JetBlue Airways – 62.08%
3. Frontier Airlines – 64.50%
4. Spirit Airlines – 69.31%
5. Republic Airways – 73.15%
6. Southwest Airlines – 73.87%
7. PSA Airlines – 75.17%
8. American Airlines – 75.33%
9. Mesa Airlines – 77.15%
10. Alaska Airlines – 77.28%
11. United Airlines – 77.38%
12. Skywest Airlines – 80.53%
13. Endeavor Air – 80.59%
14. Envoy Air – 80.71%
15. Horizon Air – 80.85%
16. Delta Air Lines – 81.03%
17. Hawaiian Airlines – 82.14%