Who wants to go to Hawaii? To…morrow. As TPG reader Peter H. discovered, United’s flying its brand-new 777-300ER from Chicago (ORD) to Honolulu (HNL) and back, giving passengers an opportunity to experience the new plane on a long domestic flight.At 9 hours on the westbound leg, ORD-HNL is roughly the length of Tokyo (NRT)-San Francisco (SFO), but since this is a flight from the mainland to Hawaii, you’ll need to redeem just 40,000 MileagePlus miles for the Polaris cabin, vs. 65,000 miles for the Tokyo flight — note that you’ll get regular domestic first-class service, though, rather than the full Polaris experience.You can use your miles to fly in both directions — ORD-HNL and HNL-ORD later in the day — but you’ll definitely want to spend the extra 17,500 for the “first class” cabin in this case, since economy is arranged in a dense 3-4-3 configuration on this plane.Availability is “wide open” on both flights, which means there are 9 or more seats available for sale and awards in both Polaris and economy class. You can also book coach and redeem a Regional Premier Upgrade to instantly confirm first class, if that’s what you’d prefer.If you can’t make this flight, there should be other opportunities to catch the 777-300ER on a “random” route — United now has 12 copies in its fleet, and with other 77W flights yet to launch, the airline’s flying this new aircraft on a variety of domestic and international routes, instead.For example, here’s where the plane operating tomorrow’s ORD-HNL-ORD round-trip has been over the past few days:Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Of course, tracking down these planes on irregular routes is easier said than done — if your seat map has been swapped for one with the configuration seen above, there’s a good chance you’ve lucked out with the 777-300ER, though. Meanwhile, if you’re looking for something to book, you can track United’s 12 777-300ERs using the links below (I’m also including an “interesting” route each plane recently flew):N2331U — (San Francisco-Honolulu)N2332U — (Newark-San Juan)N2333U — (Chicago-San Francisco)N59034 — (Newark-Beijing)N2135U — (Scheduled service only)N2136U — (Washington, D.C.-London)N2737U — (San Francisco-Washington, D.C.)N2138U — (Recent delivery)N2639U — (Chicago-Brussels)N2140U — (Denver-San Francisco)N2341U — (Boston-San Francisco)N2142U — (Recent delivery)Have you unexpectedly scored a 777-300ER on your recent United flight?