2 2 2 2 2 1928 PATCO PROMOTION FLIGHTS 2
PI-19 21 FEB 19 MANILA CORREGIDOR RT MANILA, P.I. FEB 19 2:30PM  2
PI-20 22 FEB 22 PARANAQUE BULACAN RT MANILA, P.I. REC'D. FEB 22 10AM 2
PI-21 23 MAR 01 SHIP  SHORE FLT 2 2
2 2 2 2 2 1928 PIONEER & EXPLORATION 2
PI-22 24 APR 07 MANILA CULION ISLD CULION, REC'D. PALAWAN, P.I. APR 7 10AM 2
PI-22a 25 APR 08 CULION MANILA MANILA, P.I. APR 8 5:30PM  2
PI-22b 26 APR 07 CULION  SAN JOSE SAN JOSE, P.I. REC'D. MDO APR 7 1PM 2
PI-23 27 MAY 02 MANILA APARRI APARRI, P.I. REC'D. CAGAYAN MAY 2 1PM 2
PI-23a 28 MAY 15 APARRI  MANILA MANILA, P.I. MAY 15 1PM  2
2 2 2 2 2 1928 NON-STOP FLIGHTS 2
PI-24 29 JUN 20 MANILA ZAMBOANGA ZAMBOANGA, ZAMBOANGA, P.I. REC'D. JUN 21 11AM 2
PI-24a NR JUN 20 MANILA  DANSALAN DANSALAN, LANAO, P.I. REC'D. JUN 23 9AM  2
PI-24b 30 JUN 23 ZAMBOANGA DANSALAN SILAY, OCC. NEGROS P.I. FEB 28 2PM 2
PI-24c 31 JUN 26 ZAMBOANGA SAN JOSE 2 2
PI-24d 32 JUN 26 ZAMBOANGA MANILA 2 2
2 2 2 2 2 1928 LONDON - ORIENT 2
PI-25 33 NOV 09 PUERTO PRINCESA  MANILA MANILA P.I. NOV 9 3PM 1928 2
PI-25a NR NOV 09 PUERTO PRINCESA  MANILA MANILA P.I. NOV 9 3PM 1928 POSTAGE DUE COVERS
PI-25b 34 NOV 16 MANILA  SALOMAGUE CABUGAO, REC'D. ILOCOS SUR NOV 16 12M 2
PI-25c 35 NOV 16  MANILA  HONG KONG HONG KONG 9.30 18 NOV 28 2
PI-25d 36 NOV 17 CABUGAO HONG KONG HONG KONG 9.30 18 NOV 28 2
FNC 36A NOV 17 CABUGAO BANGKOK BANGKOK, G.P.O. 3.12.28 Flown up to HK only
FNC 36B NOV 17 CABUGAO SINGAPORE 2 Flown up to HK only
2 2 2 2 2 1929 NORTHERN LUZON AIR MAIL 2
PI-26 37p MAR- APR MANILA MANILA 2 ROUND TRIP
PI-26a 37a MAR 21 MANILA SAN MIGUEL SAN MIGUEL TARLAC, P.I. MAR 21 1929 10AM 2
PI-26b 37b MAR 21 MANILA  LINGAYEN LINGAYEN, PANGASINAN, P.I. REC'D. MAR 22 12M 2
PI-26c 37c MAR 21 MANILA  SAN FERNANDO SAN FERNANDO, P.I. REC'D. LA UNION MAR 23 10AM 2
Pi-26d 37d MAR 21 MANILA VIGAN VIGAN, REC'D. ILOCOS SUR, P.I. MAR 24 11AM  2
PI-26e 37e MAR 21 MANILA LAOAG LAOAG, ILOCOS NORTE, P.I. REC'D. MAR 25 9AM  2
PI-26f 37g MAR 21 MANILA APARRI APARRI, P.I. REC'D. CAGAYAN MAR 27 11AM  2
PI-26g 37f APR 04 LAOAG APARRI 2 2
PI-26h 37h APR 05 APARRI LAOAG LAOAG, ILOCOS NORTE, P.I. REC'D. APR 11 12M  2
PI-26i 37i APR 11 APARRI MANILA MANILA P.I. APR 17 4:30PM 2
PI-26j 37j APR 11 LAOAG  MANILA MANILA P.I. APR 17 4:30PM  2
PI-26k 37k APR 11 SAN FERNANDO MANILA MANILA P.I. APR 17 4:30PM  2
PI-26l 37l APR 11 SAN MIGUEL MANILA MANILA P.I. APR 17 4:30PM  2
FNC NR MAR 31 ECHAGUE LAOAG LAOAG, ILOCOS NORTE, P.I. REC'D. APR 11 12M.  Part by surface mail
FNC NR APR 04 CLAVERIA LAOAG Same 2
FNC 37m APR 04 SOLANA LAOAG Same 2
FNC 37n APR 05 ANGADANAN LAOAG Same 2
FNC 37o APR 11 TUGUEGARAO LAOAG Same 2
PI-26m 38 APR 29 MANILA  TAYABAS LOPEZ, REC'D. TAYABAS, P.I. APR 30 9AM 2
PI-27 37A MAR 22 MANILA  PINAMALAYAN No backstamp Unable to land at Mindoro
2 2 2 2 2 1930 SPECIAL FLIGHTS 2
PI-28 39 MAY 03 ILOILO MANILA MANILA P.I. MAY 3 5:30PM Listed as via SAN JOSE. have already seen 14 covers all without SAN JOSE bkstp.
PI-28a 39a MAY 03 SAN JOSE MANILA MANILA P.I. MAY 3 5:30PM 2
PI-28b NR MAY 03 ILOILO  MUNTINGLUPA MUNTINGLUPA, RIZAL, P.I. REC'D. MAY 4 7AM SIX KNOWN
NOTE ON LONDON - ORIENT POSTAGE DUE COVERS
LOF covers posted stampless and with 32c DUES given cat number. The two covers are different from the one with 2c Rizal and charged 28c DUES. 
A cat number was assigned to the Madrid-Manila POSTAGE DUES cover. THE LOF cover should be given the same treatment.

NOTE ON AAMC 36A and 36B
Covers to HONG KONG backstamped on November 18. The five covers each to BANGKOK and SINGAPORE (all Bruggmann) I will consider as FNC. They were not flown by the RAF to their destinations but disptach by the HK Post by liner. They should be treated as covers flown up to Hong Kong only - nothing more and nothing less.

NOTE ON PI-25b
Covers back- stamped CABUGAO as no post office at small coastal town of Salomague, about 4.5 km away from Cabugao

NOTE ON 1929 CALVO COMMERCIAL FLIGHT TO NORTHERN LUZON, AAMC 37m to 37o:
The three listed covers plus two unlisted I consider as footnote covers, they being AAMC 37h: APARRI to LAOAG flights. From their origins, all were sent by surface to Aparri for flight to Laoag. Without doubt they are all commercial covers, hard to come by and worthy of being documented. But again, their origins are out of flight route. Again my cat number assignment are covers flown from Point A to Point B

NOTE ON PI-26h, PI-26i 
Listed as up to VIGAN. The many covers i have seen up to LAOAG only.
Listed as via LINGAYEN. Have seen 18 covers all w/o LINGAYEN bkstp.