Do I really need to arrive more than 2 hours early for a domestic flight out of MSP?

There are very few airlines that suggest arriving only one hour ahead, most are in the 90 minute realm and many cut off check in at 30 minutes prior to departure.

If you are late at the gate for an originating flight, then from the airline's point of view you are late, period. The fact that security was slow or check in lines were long means nothing, you bear the responsibility to be at the airport in time to do everything required before flying. The decision to write you off versus putting you on a later flight would be entirely at the discretion of the gate agent.

And seeing how MSP is a hub for Delta and a fairly big business region, I imagine early morning flights are quite busy with business travelers. And since business travelers tend to have lots of carry on, security lines are probably slower.

Websites generally err on the side of caution. You should be fine with an hour on a Thursday morning given that you're not checking luggage.

If you can check in and get a boarding pass before getting to the airport, and you are getting there on the light rail, the Skyway Checkpoint 5 stories above the light rail exit usually has a fairly short line. However, there are no United check-in desks (or even computers, as far as I remember) in that area.

There are a lot of variables that determine how long it will take to get to the gate. I live in Duluth and over the past fifteen years I have been through MSP a lot. The time-to-gate has varied between 20-minutes and 90-minutes. I can't say I have personally ever waited for two full hours, but I can also see how easily it could take that long.

Checking a bag can take some time, so the fact that you are not checking helps you and your transfers. The airline is not responsible for security/check-in delays and if you get placed on the next available flight, consider yourself lucky.

Simply- when it comes to the possibility of missing the flight, play it safe and be early- and bring something to keep you occupied in the gate waiting area.

Security line wait time 1 hour 15 minute terminal 2 2/7/2020 started on line at 5:15 for 7:20 flight. Same line two hours to get through for 7:15 flight 7/10/2020. Terminal two greatly understaffed. Arrive at least 2 hours early for early morning flights!