Easy plane to fly - loaded question!
LOL
As most have already said, the Tiny Trainer is a great starter plane; only thing with the smaller FliteTest planes (with mini or tiny in the name), they tend to get pushed around a bit more in the wind vs. the bigger planes. Does that mean you can't fly them? Heck no. You can, just know it might be a bit more of a challenge.
I'd also recommend the Simple Scout or the Cub as a good first plane, if for nothing else than they're more stable in wind due to their size.
Also, one more plus with regards to the smaller planes - get them up in the air, and the smaller they are, the harder they become to see. A tiny plane at 50 feet in the air is harder to see than one that's twice its size at the same height...The disadvantage of a larger plane is that it requires more flying space to get them turned around AND transporting them to and from the field can be a logistical nightmare if you're trying to fit it into a tiny car (trying to fit a Sea Duck into say, a Ford Fiesta or a Holden Spark is an exercise in futility LOL)
Just my two cents, and it's worth about that much.