Frontier Airlines EarlyReturns (Pre-Alignment) - Fun with code-shares and hidden cities

Seems like the Midwest tie-up has had some benefits in terms of fares not being synchronized between the two carriers. After watching DCA->DEN O/W fares on 12/26 hovering around $250 on Frontier, I was surprised this afternoon around 2PM to find Midwest selling the same seat on the Frontier flight for $149. I booked immediately (glad too, since it now seems to have jumped up to around $350 on both airlines, must be because it's ten days out, though I don't know why it was cheaper this afternoon than this evening).

Also along the same lines, Frontier has been selling tickets DCA->COS with a stop-over in DEN for about $50 cheaper than the DCA->DEN fares that I've been finding. That fare is also gone on Frontier, though Delta and NW seem to have matched.

All in all, I'm enjoying the new codeshares. Now, I just wonder if I can get Summit benefits despite having purchased through Midwest... I already got assigned a seat in Row 2 automatically by the system, I will be watching closely to ensure it doesn't change.

From recent experience it seems the systems are integrated enough to know that you're a Summit. I just bought a ticket on YX for a Frontier flight and it assigned me a seat (I'm Ascent, and if the system didn't know that, it presumably wouldn't have assigned one).

I also enjoy the fare "competition" (funny since both airlines are under common ownership, not like a true codeshare between competitors)...I paid $100 for the Midwest flight when Frontier wanted $152 for the same seat!

Yes, I should have followed up on my earlier post, when it came time to fly I checked in at the Frontier desk and it was as if I had purchased straight from them, full Summit benefits were automatically recognized and the miles posted straight away.