Editing Runway (section)

==Length==
{{Main|List of longest runways}}{{More citations needed section|date=June 2022}}
A runway of at least {{Convert|1800|m|abbr=on}} in length is usually adequate for [[aircraft]] weights below approximately {{convert|100,000|kg|abbr=on}}. Larger aircraft including [[Wide-body aircraft|widebodies]] will usually require at least {{Convert|2400|m|abbr=on}} at sea level. International widebody flights, which carry substantial amounts of fuel and are therefore heavier, may also have landing requirements of {{convert|3200|m|abbr=on}} or more and takeoff requirements of {{convert|4000|m|abbr=on}}. The [[Boeing 747]] is considered to have the longest takeoff distance of the more common aircraft types and has set the standard for runway lengths of larger international airports.<ref>{{Cite web|last=baer|first=jeff|date=2020-11-24|title=Airport Runways - Requirements and Regulations|url=https://www.airplanning.com/post/airport-runways|access-date=2021-11-27|website=Air Planning|language=en}}</ref>

At [[sea level]], {{convert|3200|m|abbr=on}} can be considered an adequate length to land virtually any aircraft. For example, at [[O'Hare International Airport]], when landing simultaneously on 4L/22R and 10/28 or parallel 9R/27L, it is routine for arrivals from [[East Asia]], which would normally be vectored for 4L/22R ({{Convert|2300|m|abbr=on|0}}) or 9R/27L ({{Convert|2400|m|abbr=on|0}}) to request 28R ({{Convert|4000|m|abbr=on|0}}). It is always accommodated, although occasionally with a delay. Another example is that the [[Luleå Airport]] in Sweden was extended to {{convert|3500|m|abbr=on|0}} to allow any fully loaded freight aircraft to take off. These distances are also influenced by the runway [[grade (slope)]] such that, for example, each 1 percent of runway down slope increases the landing distance by 10 percent.<ref>{{Cite book |url=https://flightsafety.org/files/alar_bn8-3-distances.pdf |title=FSF ALAR Briefing Note 8.3 -- Landing Distances |publisher=[[Flight Safety Foundation]] |year=2000 |language=en |access-date=2022-01-20 |archive-url=https://web.archive.org/web/20230120205706/https://flightsafety.org/files/alar_bn8-3-distances.pdf |archive-date=2023-01-20 |url-status=live}}</ref>

An aircraft taking off at a higher altitude must do so at reduced weight due to decreased [[density]] of air at higher altitudes, which reduces engine power and wing lift. An aircraft must also take off at a reduced weight in hotter or more humid conditions (see [[density altitude]]). In the worst case, this is colloquially referred to as [[hot and high]] operation, among the most challenging conditions for takeoff performance. Most commercial aircraft carry manufacturer's tables showing the adjustments required for a given temperature.

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File:No pedestrians (geograph 5985118).jpg|In the 1980s, [[Leeds Bradford International Airport]] extended its runway to take [[wide-body aircraft]] by building an [[overpass]] over the A658 road.
File:Sumburgh Airport Barrier.webm|Road crossing of ([[Shetland]]) A970 with [[Sumburgh Airport]]'s runway. The movable barrier closes when aircraft land or take off.
File:Gibraltar runway 09 & 27.jpg|[[Gibraltar International Airport]]'s runway 09/27, used to be crossed by the one road between Gibraltar and Spain.
File:Atlantis drag chute is open.jpg|A parachute may be used to slow down craft, in this case the [[Space Shuttle]] [[Space Shuttle Atlantis|Atlantis]].
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