The Six Sign Types
AIM 2-3-7 sorts airport signs into six types, and the colors tell you which one you are looking at before you can read it.
Marks the entrance to a runway or critical area, or an area aircraft may not enter.
Where you are. It names the taxiway or runway you are on.
The taxiways leading out of the intersection ahead, and which way each one goes.
The way to a place: a runway on the way out, or the ramp, fuel or terminal on the way in.
Something to know, such as an area the tower cannot see, a radio frequency or a noise abatement procedure.
Landing runway left, in thousands of feet. The last sign, a 1, stands at least 950 feet from the end.
The Red Signs
Mandatory instruction signs come in four kinds. At a towered airport you do not pass a runway holding position without an ATC clearance; at a non-towered field, you make sure there is adequate separation from other traffic before you cross.
You are at the edge of a runway. 15-33 means the Runway 15 threshold is to your left and 33 to your right. At the start of the takeoff runway it may show only that runway, such as 33.
A holding point on a taxiway that lies in the approach area of a runway. The runway number comes first, then APCH.
The edge of an ILS critical area. When ATC tells you to hold short of it, stop here.
Aircraft may not enter. Typically on a one-way taxiway or where a taxiway meets a vehicle roadway. It is a symbol, not words.
Reading a Sign Array
Before an intersection you usually meet a row of signs: the direction signs for every taxiway leading out of it, with a location sign telling you where you are now. The layout follows fixed rules, so you can read it at a glance.
- You are on Taxiway B. The location sign sits in the array.
- Turns to the left sit left of the location sign; straight ahead and turns to the right sit to its right.
- Taxiways are listed clockwise, starting with the first one on your left, each with one arrow.
- The array normally stands on the left side of the taxiway, before the intersection.
Hold Short Markings
The runway holding position marking is the one that keeps you off a runway: four yellow lines, two solid and two dashed, across the taxiway. The solid lines always face the side where you hold.
- 1Solid lines: your side. They always face the side where the airplane holds. Told to hold short, you stop so no part of the airplane is past them.
- 2Dashed lines face the runway. Leaving the runway, you are not clear of it until every part of the airplane has crossed them.
- 3Enhanced centerline: yellow dashes either side of the centerline for up to 150 feet before the marking. A runway is close.
- 4Runway holding position sign, white on red. 10-28: the Runway 10 threshold is to your left, 28 to your right.
- 5The runway.
At a towered airport you may not cross the marking without an ATC clearance, and AIM 4-3-18 says ATC issues an explicit clearance for every runway crossing. A taxi clearance to your departure runway does not let you enter or cross that runway. At a non-towered airport you make sure there is adequate separation from other traffic before you cross.
After landing, absent other instructions, taxi clear of the runway until every part of the airplane is past the holding position marking, then stop.
Hold markings appear on runways too. On runways ATC uses for land and hold short operations or for taxiing, a holding position marking and a red sign sit on the runway itself, before another runway or a designated point. Cleared to land on Runway 10 and hold short of Runway 18, you either exit before the marking or stop at it.
Runway Markings
Runway markings are white. Anything yellow at a runway end, such as chevrons or a demarcation bar, marks pavement that is not runway. This end has a displaced threshold, so it shows nearly every marking at once.
- 1Chevrons, yellow: pavement lined up with the runway that is unusable for landing, takeoff and taxiing, such as a blast pad.
- 2Demarcation bar, yellow and 3 feet wide. Yellow because it is not on the runway.
- 3Displaced threshold arrows: this pavement is available for takeoff in either direction and for landing from the opposite direction. Do not land on it from this end.
- 4Threshold bar, white and 10 feet wide: where the runway available for landing begins.
- 5Threshold markings: eight stripes, or a count tied to runway width (4 for 60 feet up to 16 for 200 feet).
- 6Runway designator: the magnetic heading of the centerline divided by ten, rounded. Parallel runways add L, C or R.
- 7Touchdown zone markings: bars in groups of three, two and one, at 500-foot intervals.
- 8Aiming point: a broad stripe each side of the centerline, about 1,000 feet from the threshold.
- 9Side stripes: continuous white lines along each edge.
How many of these a runway carries depends on its type: visual, nonprecision instrument, or precision instrument.
| Marking | Visual | Nonprecision | Precision |
|---|---|---|---|
| Designation | Yes | Yes | Yes |
| Centerline | Yes | Yes | Yes |
| Threshold | Some (1) | Yes | Yes |
| Aiming Point | Some (2) | Yes | Yes |
| Touchdown Zone | No | No | Yes |
| Side Stripes | No | No | Yes |
(1) On runways used, or intended to be used, by international commercial transports. (2) On runways 4,000 feet or longer used by jet aircraft. Source: AIM 2-3-3, TBL 2-3-1.
Do not confuse a displaced threshold with a relocated one. A relocated threshold closes the pavement before it and shortens the runway for the opposite direction as well.
A yellow X means closed. A temporarily closed runway has a cross at each end, sometimes a raised lighted one. A permanently closed runway loses its markings and lights and gets crosses at each end and every 1,000 feet. A closure may show nothing at all, so check NOTAMs and the ATIS.
Taxiway Markings
Taxiway markings are yellow. The centerline is a single continuous yellow line. Keeping the nose wheel on it does not guarantee wingtip clearance from what is beside the taxiway.
- 1Continuous double yellow: the taxiway edge. The pavement beyond, such as a shoulder, is not meant for aircraft.
- 2Dashed double yellow: the pavement beyond is meant for aircraft, such as an apron.
- 3Non-movement area boundary: dashed line on the movement side, the area under ATC; solid line on the non-movement side.
Some signs are painted on the pavement instead of standing beside it, in the same colors. Painted direction signs put left turns left of the centerline and right turns to the right; painted location signs sit right of the centerline. Painted red holding position signs, normally used where the holding position is wider than 200 feet, sit left of the centerline on the holding side.
White lines on airport pavement mark vehicle roadways: solid edges, a dashed line between lanes, and sometimes zipper markings.
Study the Diagram Before You Taxi
FlightKit airport pages show the FAA airport diagram wherever one is published, alongside the runways, frequencies and live weather. Find the hold lines on the ground before you meet them on the taxiway.
Keep Learning
Frequently Asked Questions
What do the colors of airport signs mean?
Red with white lettering is a mandatory instruction: a runway or critical area entrance, or somewhere you may not go. Black with yellow lettering and a yellow border is a location sign, naming the taxiway or runway you are on. Yellow with black lettering points the way: direction, destination and information signs. Black with a white number beside a runway is a distance remaining sign.
Which side of the hold short line do you stop on?
The side with the two solid lines. The AIM says the solid lines are always on the side where the aircraft must hold. When told to hold short of a runway, stop so that no part of the airplane extends beyond the marking.
Do you need a clearance to cross a runway?
At a towered airport, yes, every time. The AIM says ATC will issue an explicit clearance for all runway crossings, and a taxi clearance to your departure runway does not authorize you to enter or cross that runway. At a non-towered airport, there is no one to clear you, so you make sure there is adequate separation from other traffic before crossing.
Can you land on a displaced threshold?
Not from the end where it is displaced. The pavement behind a displaced threshold is available for takeoffs in either direction and for landings from the opposite direction. It is marked with white arrows and ends at a white threshold bar where the landing runway begins.
What does a yellow X on a runway mean?
The runway is closed. A temporarily closed runway has yellow crosses at each end, sometimes as a raised lighted cross. A permanently closed runway has its markings removed, its lights disconnected, and yellow crosses at each end and every 1,000 feet. A closure may have no visual sign at all, so check NOTAMs and the ATIS.
What do the numbers on black signs beside the runway mean?
They are runway distance remaining signs: the landing runway left ahead of you, in thousands of feet. A 3 means 3,000 feet remain. The last sign, a 1, stands at least 950 feet from the runway end.
Sources
- AIM 2-3 — Airport Marking Aids and Signs
- AIM 4-3-18 and 4-3-21 — Runway Crossing Clearances and Exiting the Runway
- FAA Pilot’s Guide to Airport Signs and Markings — Kneeboard Card, March 2026
This guide is written for study. Drawings are schematic and not to scale. The AIM is the authority — check the current text before you fly.