Is a military duffel bag considered over-sized luggage?

Can you answer anc876’s question about Luggage?:

I’ve used my standard military duffel for deployments in the past, but was considering using it for leisure travel because it’s light and can hold more than a standard suitcase (I’m trying to avoid the extra fees for a second checked bag). I know the checked baggage allowance is 62 linear inches. Will I end up paying over-sized baggage fees if I check it?

Luggage Backpack With Wheels

How does the luggage work for easyjet airlines?

Can you answer kostaki’s question about Luggage?:

Hi, I’m thinking of going to greece from london with easyjet. How does the luggage work? It says on their site that they have “europe’s most generous hand baggage allowance”, does that mean they dont allow luggage on the airplane and that you have to carry everything in a handbag??

Thank you

Designer Luggage Sets