Airmail, 1918, 16¢ green. Nicely centered, tied by light Washington D.C. oval and purple "Airmail Service Wash. N.Y. Phila., Washington, Jul 15, 1918" cds on first flight cover to New York City, Very Fine. Scott No. C2  Estimate $600 - 800. $0 (Image)

Airmail, 1918, 16¢ green. Tied by "Air Mail Service Wash. N.Y. Phila., New York, Jul 15, 1918" postmark on first flight cover to Washington D.C., Scott Stamp & Coin Co. corner card, Very Fine. Scott No. C2  Estimate $500 - 750. $0 (Image)

Airmail, 1918, 16¢ green. Wide margins, tied by "Air Mail Service Wash. N.Y. Phila., New York, Jul 15, 1918" postmark on first flight cover to Washington D.C., Nassau Stamp Co. corner card, Very Fine. Scott No. C2  Estimate $400 - 600. $0 (Image)

Airmail, 1918, 16¢ green. O.g., never hinged, deep rich color, Extremely Fine to Superb, absolutely beautiful; with 2006 P.S.E. graded certificate (XF-Sup 95). Scott No. C2  $150. $0 (Image)

Airmail, 1918, 16¢ green. Top margin plate block of 6 with arrow, o.g., barest trace of hinge (appears never hinged), beautifully centered amid wide margins, bright and fresh with deep rich color, Extremely Fine, choice so nice; with 2006 P.F. certificate. Scott No. C2  $1,000. $0 (Image)