Travel companies are being forced to answer the phone. A new survey suggests that what motivates a traveler when using smartphones or tablets is not necessarily the same thing as when using a desktop or laptop. The implications for advertising are important.

The Nielsen study, commissioned by call-tracking provider Telmetrics and advertising network xAd, was a mix of a survey of 1,500 U.S. smartphone and tablet users and observations of actual behavior by 6,000 Apple and Android users.

Here are the key points:

• Smartphones are used more to find and contact businesses, while tablets are used more for research, price comparisons, and reviews. In travel, tablet users went directly to familiar sites and apps (46%) or apps and sites they had previously used (49 percent) more often than they used search engines (merely 15%).

• One out of every two queries in travel results in a purchase. Thirty-three percent of mobile travel searchers want to complete the transaction within the day.

• Two out of three mobile users notice ads. Local businesses and local promotions seemed the most relevant and received the most clicks.

• US mobile device owners prefer apps, spending 81 percent of their time in apps instead of the mobile web.

The survey reports corroborate what has been reported in a separate study of mobile usage by Keynote Systems.

It also dovetails with a report by research firm eMarketer that mobile internet use accounts for 10 percent of U.S.media use but attracts only 1 percent of overall advertising spending.

Here's the infographic: