7 hours 44 Minutes: United Airlines New 2nd Longest Boeing 737 MAX 8 Route

According to ch-aviation, United has 87 737 MAX 8s, the first of which was delivered three years ago, in June 2021. Each of the 87 examples has the same layout. There are 166 seats, 16 in first class, 54 in Economy Plus, and 96 in regular economy.