Frequently Asked Questions

Tables and Explanations

Data Source

Average Timeline Timeline Chart

The average timeline contains the median time a flight spends in 3 stages. The first of these three stages is taxiing out which includes the time from the flight leaving the gate to taking off. The second stage is in the air, which includes the time spent from the flight leaving the ground to touching back down at the end of it's journey. The last stage is taxiing in, which is from when the flight touches down to the flight arriving at it's gate.

The average timeline also estimates on average of when the flight will leave and arrive relative to it's stated departure time.

Flight Reliability Reliability Chart

The reliability of an airline measures how often the airline's flights on this route are cancelled or delayed more than 20 minutes. For example, from Portland to San Francisco, Frontier is 47% reliable, which means that Frontier flights are on time 47% of the time, and cancelled or delayed the remaining time.

Flight Time By Airline Flight Time By Airline Chart

Each airline takes a different amount of time to fly between Portland and San Francisco, this is due to different operational factors on the ground, as well as scheduling of planes. Each airline's flight time is split into three stages which are described above in the "Average Timeline" section. There are also miscellaneous operational issues which are included in the below total but are not accounted for in one of the three stages.

Flights By Time of Day Flight Time By Day Chart

This one is pretty self explanatory, it represents the number of flights that leave the gate in a given hour of the day. The tricky thing here is that this is normally not a whole number since it is an average over 52 weeks. Partial numbers may indicate that a flight may be seasonal or may take off at different times due to different operational factors.

Flights By Month Flights By Month Chart

The quantity of flights from Portland to San Francisco that take off in a given month of the year. This number changes because some flights are seasonal, and almost all flights have uneven demand througout the year.

Flights By Day Of Week Flights By Day of Week Chart

The quantity of flights from Portland to San Francisco that take off on a given day of the week. Some routes only have enough demand to sustain a few trips a week, while others have many flights a day. This number is also an average across the year, and hence may not be a whole number.

Flight per Airline (per Week) Flights By Airline Chart

How many times an airline flies this route in a week. Different factors play into how often a carrier chooses to fly a given route including it's need to connect disparate routes, and demand.

Flight Time By Time of Day Flight Time by Time of Day Chart

The total flight time varies by each hour of the day due to factors such as airport traffic. More flights leaving an airport may cause higher taxi in or taxi out times. See the description of the average timeline above for a deeper discussion of each of these times.