A new report has highlighted the importance of optimising travel offerings for mobile devices, with their usage for both consumer travel planning and purchasing worldwide rocketing by a fifth over the past six months, says IT site Tech World.

The research has shown that mobile bookings are growing at a much faster rate than desktop bookings - they increased by 20% (versus 2%) over the first six months of 2014. The study also found that smartphones and tablets accounted for 21% of all hotel bookings.

The Travel Flash Report was undertaken by digital advertising firm Criteo, which studied activity on more than 1,000 travel websites worldwide in the first half of the year, analysing 300 million bookings and more than $150 billion (£88.7 billion) in bookings value.

The category with the highest mobile penetration was peer-to-peer apartment rentals at 34% globally. The average value of mobile bookings for air travel was 21% higher, and for car rentals 13% higher on mobile devices than for desktops. However, accommodation did not fare so well; hotel bookings were found to be 30% lower.

This is mainly due to a large share of mobile bookings being made on the same day; these last-minute hotel stays tend to be shorter and of lower value than week-long holiday bookings (or flights), said the report.

Interestingly, the value of bookings across categories was found to vary in relation to the device used – iPad users spent an average $600 (£350) more on packages they booked on their device compared to packages booked via Android devices. Still, the value of Android bookings for flights outpaces all other mobile devices, says Tech World.

Regions differed, too - Asia Pacific came out on top, with more than 20% of travel bookings made on a mobile device. On the other hand, Brazil and Germany registered less than 10%.

Jason Morse, vice president of mobile products at Criteo, said that the findings confirm how important it is for travel firms to make sure their websites are optimised for mobile: "Mobile is the driving force behind the exponential growth in online travel booking and sales, and that's only set to continue in the second half of this year and beyond."

He added: "With smartphones and tablets in nearly every consumer's hands today, travel marketers need to think strategically about developing a highly effective omni-channel marketing experience. That means ensuring the entire consumer experience - from the ads to shopping carts - is mobile optimised."