PHILIPINES 1941,  9th May, Cover sent from Manila to Singapore.  "First Flight by Pan American Airways CLIPPER",  1st Flight cachet in green,  Double line in violet,  Singapore Censor's Cachet in violet,  Calcutta Censor's cachet in black.  Six varieties Airmail  stamps overprinted.  Registered Manila label plus cachet Foreign Mail Section in purple on reverse.