I only upgrade on domestic flights if I have extra HK49s to burn (UA). It doesn't really matter to me if I can snag a nice exit row in coach
Too bad I can't earn status or bonus miles on Delta, otherwise I'd book a trip out to SFO to see my other half on Delta instead of UA!
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When once you have experienced being a 1K, you will forever fly the friendly skies with your eyes set on 100% mileage bonus and SWUs, for there you have been, and there you will always long to return, every year!