Thom and Jonny premiered the song, that was then titled 'An Airbag Saved My Life', on British radio station XFM on october 28th 1995:



'An Airbag Saved My Life' was a headline that Thom read in an AA ('Automobile Association', British car roadside recovery company) magazine that came through his door. But the title is also a tongue-in-cheek tribute to Indeep's 1983 disco hit 'Last Night a DJ Saved My Life'.

According to Thom, the song itself is about the feeling you get when you realise that you've just missed having a serious accident, and the feeling of elation that follows. It was inspired by Thom's feeling towards cars (Stupid Car, Killer Cars...) after being involved in a car crash with his girlfriend when he was younger. The song is one of Thom's favourites off OK Computer.
The earliest available full band performance comes from may 26th 1996 at the Bataclan in Paris:

The band was apparently inspired by DJ Shadow to use cut-up drum beats for the studio version.
This page, titled 'stuck in a frozen lake', appeared on radiohead.com during the recording of OK Computer and features a text by Thom with notes about songs that were around then.
The relevant section was not highlighted in red letters in the original page:

an airbag saved my life* in an interstella burst i am back to save the universe computer drums bass wrong lift* is hard work you been stuck in a lift we been trying to reach you thom the belly of the whale (thanks Rei xxxx) paranoid android* get busy with the shakers while im fast asleep could you stop the noise im trying ta get some rest this the place it wont hurt ever again karma police* girl with hitler hairdo everybodys friend life in a glasshouse phew for a minute there i lost myself i lost myself sit down your safe now polyethelene*will never break down swirly self announcements. stuck in a frozen lake. the penultimate place in dante's hell. last flowers till the hospital*is a sign discovered in oxford -my unhealthy obsession with these institutions. analysts may get the connection. ambulances scream past my house at all hours of the day and night like the confessionals of Larkin's "Ambulan s." let down*in the midst of monster tour the momentum getting drunk to talk bombarded by dangerously high levels of radiation from xray machines. one day, one day... climbing up the walls*both managers and record company are nervous about such a nasty sound coming out of the speakers. this is a good sign. dogwander* bring on another take better than another cake. nude* it is a mans world. and this one is very confused and will have sex with anything woman who comes within a mile radius. but feels bad about it. so doesnt. exit song (for a film)* cannot be listened to more than once in a row. which made recording it easy. or not. but what film? big boots* it was a long time ago and i cant remember. a whole orchestra watching the film and playing along. real life is dull. i am i the white lotus flying off the quay with barbara bach.
(information incomplete)
....>>>>i like the idea of you listening to our recordings with your head resting gently in emptiness. or before going out. or when you've come back. i dont like the scientists breaking down its molecular structure and teaching it in O level chemistry i ont want to have expain it but it worries me stupid. there is a lot of crying goes into making things.<<<<.... the masters tell us that there is an aspect of our minds that is its fundamental basis, a state called "the ground of the ordinary mind." It functions like a storehouse, in which the imprints of past actions caused by our negative emotions are all store like seeds. when the right conditions arise, they germinate and manifest as circumstances and situations in our lives. if we have a habit of thinking in a particular pattern, positive or negative, then these tendencies will be triggered and provoked very easily and recurr and go on recurring. With constant repetition our inclinations and habits become steadily more entr ched and continue, increasing and gathering power even when we sleep. This is how they come to determine our life, our death our rebirth.
Part of the performance of 'Airbag' from september 3rd 1997 in London can be seen in Meeting People Is Easy:



Another performance of this song, from october 18th 1997 in Paris, is also in the movie:

Thom played the song on his own for the first time since 1995 at the gig in Cambridge on february 25th 2010: