How long will a plane have to fly continuously with 900 miles per hour in order to cover the same distance as that from Earth to the next star, Proxima Centauri?

I'm not sure about the distance to the nearest star, but it's probably about 4 light-years (L-y).

1 L-y = 1.86 * 10E5 mi/sec * 3600 sec/hr * 24 hr/day * 365 day/yr

1 L-y = 5.9 * 10E12 mi and 4 L-y = 2.3 * 10E13 mi distance to star

2.3 * 10E13 mi / 900 mi/hr = 2.6 * 10E10 hr hours to star

2.6 * 10E10 hr / (24 hr/day) = 1.1 * 10E9 day days to star

1.1 * 10E9 day / 365 day/yr = 3 * 10E6 yr = 3 million years to star