TIPOGRAFIATE; MOLDOVA, OVERPRINT MONOGRAM and CAP MARE (+ TIMBRU DE AJUTOR)
overprinted either
a/ POSTA AERIANA 1920 in box (without value or, as shown, w LEI 10 LEI)
b/ 1920 PAR + value (2, 5 or 10L)  (2 main subtypes)
    *1   Thin lines, Square top left of R, left legs of letters separated
    *2   fat lines, rounded top left of R, left legs of letters merged
are all private issues without postal use
With either cancellation: Oval w BUCURESTI - IASI / A3 x N/ / Date w 1920/ I * POSTA AERIANA  (Violetblue or redlilac)
or Rectangle  w  POSTA AERIANA ROMAN/ Bucuresti -                 / date 1920  (violetblue)

Type A
 

*

Type B

 

all images courtesy Ra-Vo stamps