Do you know about this United Airlines trick?
The United Excursionist Perk allows MileagePlus members to add a one-way flight for no additional cost and / or miles to a multi-city itinerary.
The itinerary must start and end in the same region, and the free one-way cannot be in that same region. What does that mean? The free leg cannot be used during a domestic trip. Let’s use Europe as the region you are traveling to. There are many airline providers that have very affordable flights within Europe. In some cases, however, the United Excursionist perk can save you even more. Here’s how using the Excursionist Perk can look:

Chicago O’Hare (ORD) > London Heathrow (LHR) – 31,800 miles + $5.60
London Heathrow (LHR) > Frankfurt (FRA) – 0 miles + $46.70
Frankfurt (FRA) > Chicago (ORD) – 55,200 miles + $133.55
Total = 87,000 miles + $185.85
Newark (EWR) > Amsterdam (AMS) – 40,000 miles + $5.60
Amsterdam (AMS) > Lisbon (LIS) – 0 miles +$68.30
Lisbon (LIS) > Newark (EWR) – 48,300 miles + $57.45
Total = 88,300 miles + $131.35

These multi-city flights are eligible for the Excursionist perk because they start and end in the United States, but the “free” flight is in Europe, which is a different region. As with all travel hacking, free isn’t fully free – you will have some taxes to pay on the flight. When used strategically, however, this perk can help you travel within regions outside of your home location and capitalize on the long flight you took to get there.