Thorns + yellow/orange fruit, leaves silver both sides = Russian Olive
Few if any thorns, red fruit, leaves silver on bottom = Autumn Olive
Much more likely to see Autumn Olive in New England/New York but there is some Russian around.
Same genus, different species. Both are invasive plants. Both are similar to peas and soybeans in that they have simbiotic nitrogen fixing bacteria so they colonize poor soils well. But they out compete native plants then interfering with normal successions.
My grandfather never met a plant the state was giving away free for conservation purposes he didn't take...so I get to fight autumn olive, multiflora rose, and Japanese knotweed on a regular basis. Plus the normal native pain the butts like grape vines and poison ivy