Assuming I'm not using a computer program to generate a flight plan for me, for cross-country IFR flight planning in the United States, how quickly after finishing departure procedures is one supposed to get into an airway? To generalize the question a bit, I'm trying to understand when using an airway is required and when it's ok to route to waypoints outside of airways.

As a sim hobbyist one of the things I enjoy is learning about charting and route planning.

UPDATE: In addition to answers provided here, I also found it helpful to read Instrument Procedures Handbook, FAA, Ch 2, En Route Operations.

  • $\begingroup$ It's required when clearance delivery says "full route clearance, advise ready to copy..." ;) $\endgroup$
    – TypeIA
    Commented Mar 20, 2023 at 15:48
  • $\begingroup$ Usually after a SID, you are at a waypoint along the route you want to fly. If the SID ends with a radar vector, it is up to ATC to vector you to the airway they want you on. $\endgroup$
    – wbeard52
    Commented Mar 20, 2023 at 15:51

1 Answer 1


There's no general requirement for an IFR aircraft to use airways at all, regardless of if you're using a computer to generate the route or not. They only exist to make planning easier.

Of course, if clearance delivery amends your flight plan with an airway, you're required to use it. Then again, they could just as easily give you a route that doesn't include an airway when you had one in your flight plan.


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