Germany
Aerogramme Used as an Airmail Letter

German aerogramme (Greiner no. 5e) used as an envelope for a letter sheet. The airmail letter was sent from Munich (cds 8.11.51) to Cleveland, U.S.

This is the rare variant e with a folding instruction that is grammatically incorrect: “Seiten zusammenfalten, den unteren Teil des Briefes hochgeschlagen und mit der Klappe verschließen”. The correct instruction would have been: “... des Briefes hochschlagen und ...”.

The rate for an airmail letter to the U.S. in November 1951 weighing “8 gr” as endorsed on the left side of the aerogramme was a basic rate of 30 Pf for a letter up to 10 gr plus 30 Pf airmail surcharge for each 5 gr of weight. The required total franking of 90 Pf was made up by the prepaid aerogramme (60 Pf) and an additional 30 Pf stamp.

References
Greiner stands for Greiner/Greiner, Katalog der Aerogramme von Europa, 3e, 1993

Australia and Papua New Guinea
Short Paid Aerogramme

This aerogramme of Australia (Stein A-2) was sent to Woking, United Kingdom, on August 21, 1955. 

Australian stamps and airletters were valid in Papua New Guinea until March 2, 1953. On October 30, 1952  and April 17, 1953, respectively, endemic stamps and airletters were introduced.

The sender added a 3d stamp to meet the 10d airletter rate. The Australian aerogramme was not accepted, so the airletter was short paid 7d. Double the deficiency (1s2d) was converted into 42 UPU gold centimes at a rate of 1d = 3 UPU gold centimes as is endorsed in manuscript between the "By Air Mail" routing instruction and the Bristish postage due handstamp.

The same conversion rate was in place for the British currency, which explains the 1s 2d postage due handstamp.


Credits
The scan of this aerogramme was provided by Luc Jacquemin. Thanks!

References
Stein refers to Stein, The Aerogrammes of Australia and its Dependencies, 1944-1980

Singapore
"Enclosures are not Permitted"

This aerogramme (Wiegand no. 61) was sent to France on 17 AUG 98. Enclosures are not allowed for aerogrammes. Hence, the postal authorities in Singapore applied the boxed h/s "Enclosures are not / Permitted". 

Accordingly, the aerogramme was taxed as a short paid airmail letter.


Credits
The scan of this aerogramme has been provided by Luc Jacquemin. Thanks!


References
Wiegand stands for Wiegand, Katalog der Aerogramme von Asien, 2000

Singapore
D.L.O. Label

This aerogramme form, “Form Approved by the Postmaster General Malaya No. 25 (1)", was sent from Singapore to Karachi, Pakistan in 1959.

Several Karachi post offices tried to deliver the aerogramme as can be seen from three arrival cancels of post offices (2 SEP 59, 4 SEP 59 and 8 SEP 59) on the back panel. 

Finally, the Dead Letter Office was successful in identifying the correct address. A label with this address and the h/s “D.L.O. Karachi” was affixed to the front panel.

Rhodesia & Nyasaland
Short Paid Aerogramme Diverted to Surface Mail

This aerogramme form was sent from BLANTYRE, Nyasaland (machine cancel 13 FEB 1959) to New York, U.S. One stamp has fallen off. However, the original franking had not met the 1 s aerogramme rate. 

The aerogramme was h/s “Insufficiently Prepaid for / Transmission by Airmail” and diverted to surface mail, which is indicated by the h/s “Withdrawn from Airmail / By Surface Route”.

Malawi
Unpaid Aerogramme Endorsed "Pay Forward"

This aerogramme form was sent unstamped from NTAJA, Malawi (cds 20 Jan 1989) to Karachi, Pakistan. The sender endorsed "PAY FORWARD" in a stamps' stead.

The most likely meaning is "Pay it Forward". According to Wikipedia, "Pay it forward is asking the beneficiary of a good deed to repay it to others instead of to the original benefactor". Here, the sender asked the Post Office to pass on the aerogramme for free, which they did, though, after taxing the aerogramme "35/35" tambala, the Malawian currency.

There are no signs that the postage due was collected by the Pakistani postal authorities. So, it is still in the realm of possibility that the Pakistani postal authorities did the good deed the sender has asked for. If not, it finally was the addressee who paid the amount postage due.


Credits
Thank you, stampboard members HayeSmyth, psestamp and GlenStephens for pointing me to the concept of "Pay it forward". The stampboards thread related is here.

Australia
Crash Mail

This aerogramme (Stein A-6) was transported on board the Lockheed L-749A Constellation, registration G-ALAM, which crashed on Singapore Kallang Airport on March 13, 1954.

A violet boxed handstamp "Salvaged Mail / Aircraft Crash / Singapore 12.3.1954" was applied on the front panel of the aerogramme which was salvaged form the burning airplane.

Article from The West Australian (Novermber 17, 1954)

Australia
Forces Mail Air Letter from "HMA Ship"

This airletter (British Army form W.3077) was sent to Brighton Le Sand, New South Wales. The message on the writing panel is dated December 16, 1945.

The airletter shows the machine cancel "Post Office Maritime" in red and the "H.M.A. Ships" handstamp.

The sender added the endorsement "Forces" to "Air Letter" and "Free". Australian troops serving in the Middle East and the South Pacific had, with some exceptions, the advantage of free postage on surface mail. Transfer by airmail was subject to an additional fee.

It is most likely that the sender was based at a ship of the Royal Australian Navy in the South Pacific.

Australia
Invalid Stamps Used on Aerogramme Form

This is a privately manufactured aerogramme form licensed by the Australian Postmaster-General (permit no. 8, manufactured by McCarron, Bird & Co, Melbourne). It was sent from Melbourne (cds SHIP MAIL ROOM MELBOURNE 29 MY 62) to the sender's postal chess partner in Luedenscheid, Germany.

The aerogramme is franked with stamps of Nauru with a total face value of 10 pence. The stamps of Nauru were never valid in Australia.

In his message the sender states:

"This time I am answering with some stamps of Nauru [...] However, I would like to point to the fact that I cannot ask for a clear and light cancellation of these stamps at the post office. The more I insist on this the higher is the risk that the stamps will not be accepted, which would result in the aerogramme to be sent by surface mail.

It is in particular complicated with the stamps of Nauru. I could send the letters to Nauru first to feed them into the postal network there. As Nauru does not have an airport, this will result in about the same transit time as for a seamail letter from Melbourne."

Apparently, the sender wanted to offer his chess partner with the correspondence not only stamps of Australia but also from Pacific Islands. He hoped that the stamps of Nauru, which were not valid in Australia went unnoticed through the Australian postal service. 

It is interesting that he mentions the risk of the Nauru stamps being detected but the consequence he saw is a little bit odd: it is not only that the letter would have been diverted to surface route but that it would have been taxed as short paid. I guess his chess partners would have loved to pay for each move they receive.


References

Thank you, Allan and stampboard members Tassie_Stamps and GlenStephens, for the information that Nauru stamps were never valid in Australia. Here is the link to the stampboards thread concerning this matter.

A list of the manufacturers of the Australian permit aerogrammes is included in the article "Australian Private License Airletter/Aerogrammes 1946 to 1969" by David Collyer in the May 2012 issue of the Postal Stationery Collector.

Ethiopia / France
Special Fee for Poste Restante Service

Aerogramme (Müller/Wiegand 11d, Watermark IMPERIAL AIR MAIL “B”) sent from Ethiopia to Arbois, France, with the instruction “POSTE RESTANTE”.

Four 0,10 F postage due stamps were affixed as a fee for the “Poste restante” service.

The Universal Postal Union (UPU) rules allowed countries to charge a fee for incoming international mail sent to a poste restante (general delivery) address provided those countries also imposed a charge on domestic poste restante mail.


References
Müller/Wiegand stands for Müller/Wiegand, Katalog der Aerogramme von Afrika, 1995