I scratch my head at carriers flying to TVC from the likes of BOS and LGA.
A little Googling found a 2013 airport press release noting TVC non-stops from ATL, EWR, DEN and LGA (AA). This isn't a covid-popularity anomaly. https://www.tvcairport.com/delta-atlanta.php
The TVC hotel situation is a little constrained, but, frankly, people would be wise to use TVC and non-stops as the preferred airport for resorts within maybe 80 miles, everything on the Lake Michigan shore from Ludington north.
TVC, primarily in the summer and fall, is unique in that air service is oriented toward three major segments:
1) People with ties (e.g., family and or property) to the region who have moved to coastal markets
Lots of families that grew-up in the Midwest, especially Detroit, Chicago, Indianapolis, and even St. Louis spend time vacationing in Northern Michigan. Many families have cottages on the lakes/woods that are passed down through the generations. Many of the children and great-grandchildren that grew up in the Midwest, particularly the upwardly mobile and ones from wealthier families, have moved to coastal cities. They still travel back "home" or to the family cottage, for the family reunion week, and visit Northern Michigan in summer. Michigan was ranked #1 in the early 2000s for "brain-drain" hence so many recent college graduates in the era migrated to coastal markets for jobs/income/big-city-lights.
In recent years, the amount of real estate being bought and/or built from East Coasters have drastically increased. Compared to similar destinations in the North East like MVY, ACK, or other resorter communities, the price of real estate is a steal in Northern Michigan and way more affordable. Increasingly all these "mega-cottages" that are $1M+ are going up in the favored gold coast areas around and near Lake Michigan. A lot of that money is coming from East Coasters.
2) Year-round and seasonal residents who travel outbound
Northern Michigan has always been a big retirement market for Midwesterners, but similar to above East Coast and others out of region are taking notice.
The seasonal population swells in Northern Michigan, and they do like to travel outbound as well.
In addition with the dynamics of COVID and many tech and finance people working remotely into the summer, many of those types with vacation homes in Northern Michigan may be spending more time up there this summer and less time still in the office and/or cities.
3) Destination travel from outside the Midwest / driving radius
Increasingly more people coming in from places like Florida and Texas to beat the summer heat. Some don't have ties at all to the region. They enjoy that its a lot cooler than those places and word is getting out.