North German Lloyd
To speed the mail from incoming liners an experimental flight took the mail brought ashore from the North German Lloyd steamer "Karlsruhe", which arrived at Galway from New York, on to Croydon. Colonel Charles F. Russell departed from Oranmore at 7.30 am in a Vickers Vixen, arriving at Croydon at 11.35 am, with two stops at Baldonnell and Sealand for fuel. A vignette was issued by the company and applied to the mail. A local mail from Tire was also carried.
26th August 1929. Karlsruhe-Galway-London.
No Value
Green (Some blue vignetets also exist).

Karlsruhe-Galway-Londin. Air Mail Magazine Volume 2, p. 368, A. Phillips (1940)