Regular United Airlines seats appear as fare code "X," while these hidden awards appear as fare code "XN." You'll only see the hidden seats when you're logged into your United Airlines account ...

Southwest Airlines is offering 30% off many flights this summer and fall, but the deal isn't available on every ticket.

These fare class codes also apply when making flight changes. If only a higher fare class is available, you may need to pay the price difference, even when using United's same-day-change policy.

Use Southwest's Low Fare Calendar with the promo code applied to search for your desired route. I did a quick search for flights from California to Hawaii. I wouldn't say there were a ton of ...