Thailand. (Sarawak). 1931. Air Mail envelope addressed to Bangkok bearing Sarawak SG 72, 2c bright purple (top margin with plate number 2), SG 78, 3c green (top margin with plate number 2), SG 79, 4c purple (top margin with plate number 2) and SG 82, 8c bright rose tied by Kuching date stamp 'Dec 2nd 1931' with blue 'By Air Mail' label and endorsed 'Alor Star - Bangkok (Siam), carried by sea to Singapore '4th Dec' and Air connection missed and onward by surface mail with Bangkok arrival 'Dec 9th' on reverse and bold boxed 'TOO LATE' instructional struck over label in violet applied in Siam.
Unusual and very attractive cover.