Pyjamas OR Pajamas?

The word pyjamas (or pajamas ^US spelling) is a very commonly mispelt word. According to wikipedia and the American and British spelling differences here's a little bit of history and why.

The 'y' represents the pronunciation of the original Urdu ”pay-jama”, and in the 18th century spellings such as "paijamahs" and "peijammahs" appeared: this is reflected in the pronunciation (with the first syllable rhyming with "pie") offered as an alternative in the first edition of the Oxford English Dictionary. Both "pyjamas" and "pajamas" are also known from the 18th century, but the latter became more or less confined to the US.^[23] Canada follows British usage; the spelling "pajamas" is virtually unknown.