Philippine Airlines (PAL) was founded in 1941 and is the flag carrier of the Philippines. PAL has been given the backronymic (back acronym) nickname of “Plane Always Late” since at least 1978.
 
Japan Airlines (JAL) has the similar nickname of “Journey Always Late.”
 
   
Wikipedia: Philippine Airlines
Philippine Airlines, Inc. (abbreviated as PAL and also known historically as Philippine Air Lines) operating as Philippine Airlines, is a flag carrier of the Philippines. Headquartered at the Philippine National Bank Financial Center in Pasay City, the airline was founded in 1941 and is the first and oldest commercial airline in Asia operating under its original name. Out of its hubs at Ninoy Aquino International Airport of Manila and Mactan-Cebu International Airport of Cebu City, Philippine Airlines serves twenty destinations in the Philippines and 26 destinations in Southeast Asia, South Asia, East Asia, Oceania and North America.
     
Google Books
Asian Finance
Volume 4
1978
Pg. 78:
Passengers have given up saying PAL stands for “Plane Always Late”; instead, they now say, “Prompt At Last” which may not be all fortuitous.
 
Google News Archive
4 November 1981, The Age (Melbourne, Australia), “Rich Man, Poor Man” by Judith Womersley, pg. 11, col. 3:
A FEW days ago we have landed after an eight-hour flight, late, (PAL means Plane Always Late—local joke) in Manila, the capital on the island of Luzon of the 7107 islands that make up the Philippines.
   
Google Books
Philippines, a Travel Survival Kit
By Jens Peters
South Yarra, Vic., Australia: Lonely Planet Publications
1987
Pg. 82:
AIR
Philippine Airlines (PAL) operates an extensive domestic network. Cynics insist that PAL means ‘Plane Always Late’ or ‘Passengers Always Late’.
 
Google News Archive
14 June 1995, Manila (Philippines) Standard, “Vantage Point” by Tara S. Singh, pg. 12, col. 3:
It seems PAL has been living up to its “billing” (Plane’s Always Late).
   
Time magazine
Bad News Bird
By ANTHONY SPAETH Monday, Oct. 05, 1998
(...)
For Filipinos it was an ignoble end to a venerable symbol of national pride—although they had long enjoyed joking that PAL stood for Plane Always Late.
     
JetPhotos.Net Forums
CanVoodoo
06-10-2009, 02:41 PM
Airline nickname list
This will not be new to most people here—it is an expansion of a list that has been around for years.
(...)
Philippine Airlines (PAL)
Philippines Always Late
Plane Always Late
Please Avoid
     
Live in the Philippines
PAL, Plane Always Late
DECEMBER 24, 2010 BY GENSAN CHRIS
Over the last 25 years or so, Philippine Air Lines (PAL) has always been my carrier of choice and I have always had good service from them until now that is. I do not like to say things just because I had a bad experience but this time there were 250 of us who suffered the same bad experience