Economic means, primarily, of or relating to the economy or economics. Economical means prudent, efficient, or thrifty. The adjectives were once variants of each other—and some dictionaries still list them this as such—but the differentiation is well established and generally borne out in real-world usage.
Many private sector forecasters are expecting Japanese economic growth to return to positive territory in the third quarter. [Wall Street Journal]
Through six economical innings, he held the Padres to only one hit. [Los Angeles Times]
On the other hand, every opposition party has promised to increase the CIT — the tax that is most harmful to economic growth. [Globe and Mail]
Generation Xers, those born to the Baby Boomers between 1960 and 1980, could be headed for economic disaster. [The Australian]
” The Kingsroad” is a particularly eventful hour of Game Of Thrones, layering on plot point after plot point in a brisk, fairly economical matter. [AV Club]
Drivers are forking out only slightly more for fuel than 30 years ago because cars have become more economical, according to new research. [Scotsman]