upwardly mobile buyer

日本でもスーパーマリオとコラボしたCMで話題となっているMercedes-Benz GLA250のレビューです。
mobileはmobile phoneなどでお馴染みの単語ですが「動かしやすい」という意味の他に「(社会的地位仕事住まいなどを)簡単に変えることができる」という意味があり，upwardly mobileで「将来有望な」という意味があります（『プログレッシブ英和中辞典』小学館）。よって記事のupwardly mobile buyers in their 30’sは「将来有望な30代の購入希望者」と解釈できます。（Koyamamoto）

Pampered Baby Knows How to Crawl
Review: 2015 Mercedes-Benz GLA250
STEWARTSTOWN, N.H. — When Robert Reed and his family turned their all-terrain vehicles onto a dirt trail in far northern New Hampshire, he was surprised to see tracks from a bigger machine. The rough trail is typically used only by riders of all-terrain vehicles frolicking on a new 1,000-mile regional network of A.T.V. trails called Ride the Wilds.
… Mercedes predicts that the GLAs will appeal to upwardly mobile buyers in their 30’s. But such vehicles also likely to attract those who once bought midsize cars or S.U.V.s and are interested in a smaller vehicle with “premium content,” Jeff Schuster, the senior vice president for forecasting at LMC Automotive, wrote in an e-mail.
But despite Mercedes’ marketing wizardry and the GLA’s sport-utility tag it’s a good guess that Mr. Reed and his A.T.V.-riding family have seen their first and last GLA on anything that could be remotely considered off road.
http://www.nytimes.com/2014/11/09/automobiles/autoreviews/review-2015-mercedes-benz-gla250.html?hpw&rref=automobiles&action=click&pgtype=Homepage&module=well-region®ion=bottom-well&WT.nav=bottom-well&_r=0