to Isthmian Airways

Chronology and dating of the Isthmian timetables

I have never seen an Isthmian timetable with an identifiable date. However, the chronology of the four Isthmian timetables shown on this site is easy to ascertain - there is enough information in the timetables to establish the order in which they were issued (see the table below).

This information also provides useful when trying to pin down the years they were issued. Nevertheless, the result is just an educated guess.

All figures relate to Day 1 in May 1929, when the service was inaugurated.

Time-
table		 Number of miles flown Number of flights Number of passengers One-way fare Round-trip fare Additional info

A
"six times around the world"
(= approx. 144,000)
"landings every fifty miles" *)
(= approx. 2,880)
no info
$10.00
$15.00
  

B
> 384,000
> 5,000
> 19,000
$10.00
$15.00
  

C
no info
no info
> 45,000
$7.50
$12.00
Cover shows a United Fruit liner built in 1932

D
no info
no info
> 50,000
$7.50
$12.00
Cover shows a Grace liner built in 1932
*) Corresponding to the distance between Cristobal and Balboa, at the northern and southern ends of the canal respectively.

All timetables show six flights a day, with three in each direction. Assuming this was also the original schedule at the time of inauguration in May 1929, timetable A allows for 480 days of operation. Since there were also charter flights it is highly likely that this figure was lower. Still, I think it is fairly safe to assume that timetable A was issued sometime in 1930.

As for timetable B, I don't know why the number of miles flown seems to have increased much more than the number of flights when comparing with figures given in timetable A. Charter flights over longer distances? Since the fares are the same in both timetables, I assume timetable B wasn't issued later than 1931. When checking old OAGs you notice that fares in 1931 were often lower than in 1930 due to the depression, even more so in 1932 and 1933. However, with the much higher figures stated in timetable B, it couldn't have been issued in 1930. I settle for 1931 as the most likely year.

Timetables C and D, having much higher figures for the total number of passengers flown, were possibly issued in 1933. Both covers show passenger liners which, to the best of my knowledge, were built in 1932. Unfortunately, I have no exact information on when Isthmian terminated its service. One source says it operated only 3 years, which is apparently wrong. I have also heard the season 1934-35 being mentioned, as well as 1936.

/Björn

If anyone has additional information in order to shed some light over the "dating mystery", please e-mail me.

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This page last updated September 15, 2009.