Route notes
Why this routing works
This itinerary is built as a one-direction multi-stop loop: Denver to Tokyo first, then onward to Vienna and Lisbon, before the final return to Denver. That sequencing avoids backtracking and turns the trip into a continuous westbound arc across the Pacific, through Europe, and home across the Atlantic.
With three weeks total, the route spreads the longest flying over the full trip rather than stacking major long-haul segments together at the start or end. Tokyo works as the transpacific entry point, while the Europe portion is handled as an onward progression from Central Europe to the Iberian edge before the return home.
Ticketing this as a single multi-stop journey can simplify the long-haul structure compared with piecing together separate round-trips. The stop order is straightforward, with each city connected by a flown sector and no surface gaps to manage between stops.