Almost all of the major airports in the United Kingdom are single-runway (or functionally-single-runway) installations, with only two of the very busiest (Heathrow and Manchester) having as many as two runways (although Heathrow has a third under construction).

In 2026, only a handful of major UK airports operate with two or more "active" runways for commercial traffic. The most notable is London Heathrow (LHR), which uses two parallel runways (09L/27R and 09R/27L) to handle its massive global volume. Manchester Airport (MAN) is the only other major English airport with two fully independent parallel runways. While London Gatwick (LGW) technically has two runways, they are too close together to be used simultaneously; the second "emergency" runway is typically only used when the main one is closed for maintenance. Other airports like Belfast International and Glasgow have crosswind runways, but these are rarely used for simultaneous operations. This lack of dual-runway infrastructure at secondary hubs like Stansted or Luton remains a primary constraint on UK aviation capacity in 2026, often leading to the intense congestion and "stacking" seen during peak travel hours.