The cover shown here, sent on May 6, 1940 from Kerkrade in The Netherlands to Lisbon, Portugal was featured in the July 2003 ASNP Newsletter. The original write-up was by John van Rijsdam, but after publication additional information was received from several sources. The comment below came from Mr. J.H.Verschuur.

Per April 2nd 1940 the KLM opened a twice weekly flight to Lisbon with a stopover in Oporto (Portugal) for refueling. The KLM planes left Schiphol/Amsterdam every Tuesday and Saturday at 8 o'clock. Refueling took place in Oporto from 16.40 to 17.40, and at 19.00 o'clock the plane landed in Lisbon.

This schedule had a purpose. The days after the arrivals (Wednesday and Sunday) there was a through connection to Horta (Azores). On the following Thursdays and Mondays there were through-connections by PANAM-Clippers via Bermuda to Baltimore (USA).

The return flights took place on Monday and Friday, leaving Lisbon at 7.00 o'clock, stopover in Oporto from 8.30 - 9.30 and arrival at Schiphol/Amsterdam at 16.35.

Due to the fact that France was already at war with Germany, the planes could not fly in a straight line. A detour had to be made and the flights were made over the sea from start to finish, which caused also the refueling stopover at Oporto.

There were 11 flights Amsterdam-Lisbon and 10 return flights Lisbon-Amsterdam. The outgoing flight were from April 2nd until May 7th 1940, the return flights from April 5th until (Tuesday) May 6th 1940.

All these details I took from PO&PO's 20th edition of their series "Posthistorical Studies". The title of this study is: "North Atlantic connections with stress for the years 1939-1945", written by Hans E. Aitink and Elbert Hovenkamp. This study counts 311 pages and is written in the Dutch language.

Now back to the cover in question. It was "X-hour" for Hitler on Friday morning of the 10th of May at 03.55 hours. On that very moment the German troops crossed over the Dutch border, whereas the German planes were already on their way to the Netherlands to bomb the airfields and harbors, as well as planes with parachute-troops for landings at airports and nearby important bridges.

The KERKRADE COVER was canceled on Monday 6th of May 1940 at 20.00 hours. Now the unsolved question remains: how many hours dit it take to deliver this cover just in time for the Lisbon-flight leaving Schiphol at 08.00 hours on Tuesday the 7th of May 1940? It is my opinion that the 12 hours' period between these two points of time should have been sufficient to catch the 7th May Lisbon connection. But apparently for reasons unknown it missed this connection. As no further flights were made, due to the fact that shortly afterwards the war started, the cover could not be dispatched and was returned to its sender.

The fate of KERKRADE was rather quickly decided on May 10th 1940. As the German troops were already in Maastricht at 08.00 o'clock that day, it can be assumed that KERKRADE was already seized by the Germans at about 05.00 - 06.00 o'clock in the morning of the 10th of May 1940. KERKRADE was liberated by the American troops on Thursday October 5th 1944.