If your itinerary involves a stopover, give the Multi-City tool a look to potentially save some dough.

​A recent trip called for me to go from San Diego to Vancouver. Not exactly the most frequent, in-demand flight route. Here was the best itinerary via Delta based on my schedule:
A bit pricey albeit fair considering the last-minute nature of the booking. But we can do better.

Now that you know there’s a connecting flight to get from Gaslamp to Gastown via Seattle, search for your flight w/ the Multi-City Tool and break it up accordingly:
Select those same exact two flights, and peep game:
Search for your flight w/ the Multi-City Tool and break it up accordingly.
From $448.50 to $375.40. But this is the Mile Hype Club… We can do even better.

One of the perks of the American Express Platinum and Premier Rewards Gold charge (read: not credit) cards is the annual airline fee credit. You get $200 a year w/ Platinum, $100 a year w/ the PRG. This benefit covers incidentals but not airfare / ticket purchases directly. Check-in luggage fees? It’s on Amex. Seat upgrade? It’s covered. In-flight booze? They got you.

But try and use this benefit towards directly purchasing a flight and you’ll be out of luck. Instead, if you buy Delta gift cards in $50 or less increments with these cards, your airline fee benefit will be triggered and you’ll get reimbursed (almost) instantly. Delta allows up to 3 gift cards to be applied at time of purchase, so our grand total came out to (-$150) $225.40. Just about half off our original quote.
One major caveat to this: beware of delays. If routes are booked separately as so and not on the same ticket, it’s unclear whether the Sky Team (Delta, Korean, KLM, Air France) or Star Alliance (United, Air Canada, ANA, EVA, Lufthansa) airlines will be responsible for rebooking your flight. So far, the only airline group to confirm that they’ll cover any of their own missed flights due to delays on broken-up itineraries is Oneworld (American, British Airways, Cathay, JAL).

For completeness and curiosity’s sake, here was how I booked my return trip: 12,500 Aeroplan miles transferred via Amex for an Air Canada award flight.
The combo of a diverse pool of points, Amex airline fee benefits, and leveraging the Multi-City search tool was a great move in getting me from carne asada fries to poutine with enough cash for some LA dirty dogs in one weekend.