1922, Eagle in Flight, imperforated trial color proof of 50c in yellow and black, block of four printed on paper without watermark, overprint ''Muestra'' at top left of each stamp, full OG, NH (bottom stamps) or hinged, VF and scarce multiple, Est. $500-$600 (Image)

1928 (May 28), Pioneer Flight cover from Mexico City to Italy, franked by Eagle 50c blue and red brown, delivered by Flight Nuevo Laredo to San Antonio and New York (May 31) upon arrival to Rome uprated by two Italian dues of 50c and 2L (No. J10, J16), three-color Air Mail label, violet boxed ''T. L.2,50'' and all appropriate markings, repaired tear did not affect the stamps, otherwise F/VF, Est. $150-$200 (Image)