The airport claims that the "pioneering new concepts" by Grimshaw, Zaha Hadid, HOK and Benoy represent a step change in global airport design and "push the boundary of what an airport could and should be".
According to Heathrow, each was asked to come up with bold ideas to create a world-class sustainable airport that would deliver innovations in passenger service, integrate local communities and showcase the best of British design.
Affordability and flexibility were also key to the brief to ensure that Heathrow remained adaptable in the fast-paced world of global aviation.
The shortlist of architects announced today alongside the visionary conceptual images.
The next phase of the tender process will further test their creativity before a final concept designer is selected in July.
Zaha Hadid's vision.
Heathrow’s Head of Design Barry Weekes said: “From welcoming Concorde to the landmark Terminals 2 and 5, Heathrow has always been at the heart of showcasing the best of British innovation and design.
"The visionary concepts are just the start of a dialogue which will fundamentally redefine what an airport is, how it looks and feels, how it interacts with its environment and an increasingly demanding generation of new passengers and importantly enhancing how it connects with the communities around it.
"Our ambition for expansion is to transform Heathrow once again – building Britain a value for money global gateway at the forefront of sustainable development and innovative design.”