You don't need a lot of space to see everything, because you can store information in your memory.

You narrow down your options by having knowledge like "I have points on these airlines so I want to fly on Star Alliance which has partners that fly out of (quick check) these airports, so let's plan the itinerary in this way..."

I just got back from traveling the last 3 months (40 flights, 6 continents) and planned all of it from my phone. From flights, to hotels, to visas.

And it's simply better than a laptop. 4 tabs in 4 browsers means you're distracted, you're not pruning useless information, you don't know what you don't know.

I do 95% of my work on my phone too, and I wouldn't have it any other way.