This logo was introduced in the early 1940s. It was a simplification of an earlier shield logo first introduced in 1936.
Around the early 1950s, the shield logo was altered with a slight slant added.
An oblique vertical "spike," blue on bottom and red on top, running through the name "United" written in a black or blue serif italic font.
In 1998, United started implementing a new identity created by Pentagram.
In 2010, United acquired Continental Airlines in a merger completed later that year. Inititally, the entities remain separate, with United continuing to use a variant of the slant U logo. The logo and livery was presented with the merger on May 3 and keeps most aspects of Continental's identity, but replaces the Continental name with United.
The initial merger identity was replaced after only three months. On August 11, 2010, a tweaked logo and livery was revealed. Yet the logo now only has the word "United" on it and it is written in capital letters using a simple sans serif font.
The merger was officially completed on October 1, 2010.