Blue and yellow flags are predominately used to represent nations, but appear across a number of other fields, too. Several national flags involve the colours blue and yellow; the majority are made up of only these two colours, while some blue and yellow flags also contain a third, very minor colour, for example in the form of a star or similar emblem.
European flags that are blue and yellow in colour include the national flag of the Ukraine, which features two horizontal stripes, with the top being a light blue and the other a yellow in colour. The current flag has been used since 1992, although the Ukraine’s two national colours stem from the heraldry of the city of Lviv, and blue and yellow have been the colours of the Ukraine’s national flag since 1918. Sweden’s flag features a blue background and a yellow Scandinavian cross, with the colours originating from the Swedish national arms. The Swedish flag was adopted in 1906.
A set of islands which make up part of the West Indies, the Lesser Antilles is home to many blue and yellow national flags. The flag of Barbados consists of blue outer panels and a golden panel in the centre, though it does feature a black trident in the middle, too. This flag was designed by Grantley W. Prescod, who won a flag design contest, and represents the island’s sea, sand and separation from its colonial past. The primary colour on the flag of Aruba is blue, with the flag design also containing yellow bars at the bottom. Like Barbados’ flag, Aruba’s design symbolises the sea, while the bars are indicative of the island’s desire for independence.
Blue and yellow designs are quite common among the islands of the Pacific. Nauru’s flag contains a blue field as a symbol of the Pacific itself, while a yellow line in the design represents the Equator, which is geographically near to the island. Palau’s simple flag features a light blue background, symbolic of the ocean, and a yellow globe in the centre. This globe represents the moon, an important element of life on the island.
Blue and yellow flags aren’t limited to representing nations. In the sport of motor racing for example, a blue flag featuring a yellow diagonal stripe appears to warn drivers that they are about to be overtaken by a faster driver, to ensure they allow the upcoming vehicle to pass safely. In the United States, the state flag of Nebraska, among a handful of others, features an emblem and motto coloured in blue and yellow; the emblem contains a craftsman striking at an anvil. The U.S. Navy’s flag is similarly coloured with regards to its background, with a ship and eagle design in its centre.