Close your eyes, and imagine the great frontier! Now throw into the mix, cross-continent flight travel at affordable prices via Allegiant Airline, from the rustic city of Billings, Montana to the hair-pulling hustle and bustle of Baltimore/Washington International Thurgood Marshall Airport.

Yes, it's true! The exhilarating swirl of cattle wrangling and monumental landscapes blend delightfully into an eclectic fusion of seafood traditions and colonial history. This might sound as fantastical as a childhood fairytale, thanks to the aviation marvels of Allegiant Airlines, but it's "hurry up and book your ticket" time. You are about to take flight on an unforgettable journey that would effortlessly turn the pages of your travel diary, as fast as your heartbeat would ricochet against the sides of your chests for missing out!

Straight from Billings, where the Yellowstone River flows with the secrets of an ancient world locked-away within its sedimentary silhouettes, Allegiant Airline offers an invitation to board an aircraft flying to what was once the Linchpin in the Revolutionary War, against the Britishers.

Before you plan your flight, it’s imperative to utilize Allegiant’s online check-in facility. This powerhouse of convenience reduces your on-ground time at the gates and provides you with the required boarding pass with the tap of a button, right on your mobile device. With your captivating itinerary in head-on mode, remember that the boarding process starts 45 minutes before your intended departure. Buckle up and wear that anticipation on your sleeve like a badge; Billings is about to serenade Baltimore in a spectacle of skies.

The direct passage from Billings to Baltimore/Washington International Thurgood Marshall Airport steps over an impressive distance of 1,569 miles. Onboard the agile and robust MD-88 aircraft, the journey takes around 4 hours and 43 minutes before you land (with that full passenger belly in tow) at one of the world's busiest airports, named after Thurgood Marshall, the first African American judge to serve on the U.S Supreme Court. Now, isn't that entertainingly enlightening?

Ready your taste buds as they prepare on your flight for an encounter with Maryland’s tantalizingly delicious crabs, notorious for their fabled savors. For you bookworms looking for a smörgåsbord of literature, the arrival at Washington offers an ideal library crawl to explore their literary jewels. Besides, a visit to the American Visionary Art Museum can also trigger your wanderlust into overdrive.

The categorical fun and exploratory promise jetting you from Billings to Baltimore via Allegiant Airlines sparkles like an opportunity-in-transit. Request extra pillows and blankets for a comfy cabin experience. Make sure to snap some in-flight photos against the setting sun to catalog your magical journey in high-flying style.

So, trade those cowboy boots for a pair of navigation sneakers, because Allegiant Airlines now helps you traverse the yawning plains of Montana to the bustling streets of Baltimore/Washington without missing a moment of joy, discovery, or satire.

At the end of the day, a journey with Allegiant Airlines doesn't merely shuffle you geographically but it tranquilizes your flight anxiety with an entertaining twist, while opening your horizons to an engaging transcontinental adventure. So sit back, relax, and enjoy the ride. This is more than just about cruising altitudes; it’s about bridging continental memoirs laden with rich divergence and unity.