Before a recent Virgin America flight from San Francisco to Seattle, I decided to credit the miles earned on the flight to my Alaska Airlines loyalty account instead of my Virgin America account.

Because I’d already booked the ticket with my Virgin loyalty number, I had to call up Virgin America to make the change (they don’t allow you to edit that online, though I could have entered my Alaska number initially when booking).

Why credit the flight to Alaska?

With Alaska, you earn miles based on how far you fly.

Even on Virgin America flights, if you credit the flight to your Alaska account you’ll earn the amount of miles that you fly.

With Virgin, you earn miles based on how much money you spend, as it is with most airlines now.

This was a Black Friday sale flight, so I didn’t spend a lot of money.

Here’s the roundtrip base fare for me and my girlfriend together:

Since she doesn’t have an Alaska account, she credited her miles to Virgin.

Here is what she earned:

I credited my miles to Alaska.

Here is what I earned in Alaska miles for the same flight:

A couple factors went into my decision:

• I received a 50% bonus for having elite status with Alaska, which I earned through a status match from Frontier.
• Even without the bonus, I would have earned more miles than my GF did crediting her flight to her Virgin account.
• Here’s the math: Now that Virgin America and Alaska are merged, you can transfer your VA miles to your Alaska account at a ratio of 1.3 to 1, meaning Virgin miles are worth more than Alaska miles. Even so, the 160 VA miles she earned per flight would only equal 208 Alaska miles if transferred.

So why didn’t she create an Alaska Airlines account and credit her miles to Alaska?

Alaska recently gave out 10K miles to VA members who didn’t have Alaska accounts or had both accounts, so she was hoping to get in on that.

It’s not looking good for her though, as it appears Alaska is only giving miles away to people who had active VA accounts before December 2016, which she didn’t.

How do you decide where to credit your flight miles?