He says no:
I never killed or injured anyone.... In 1970, I co-founded the Weather Underground, an organization that was created after an accidental explosion that claimed the lives of three of our comrades in Greenwich Village. The Weather Underground went on to take responsibility for placing several small bombs in empty offices — the ones at the Pentagon and the United States Capitol were the most notorious — as an illegal and unpopular war consumed the nation.
The Weather Underground crossed lines of legality, of propriety and perhaps even of common sense. Our effectiveness can be — and still is being — debated. We did carry out symbolic acts of extreme vandalism directed at monuments to war and racism, and the attacks on property, never on people, were meant to respect human life and convey outrage and determination to end the Vietnam war.
Peaceful protests had failed to stop the war. So we issued a screaming response. But it was not terrorism; we were not engaged in a campaign to kill and injure people indiscriminately, spreading fear and suffering for political ends.
There is no doubt, however, that at least under current law, he would be considered a terrorist. Here is a definition of terrorism in U.S. law (22 USC 2656f(d)f(2)) (there are others as well but similar):
the term "terrorism" means premeditated, politically motivated violence perpetrated against non-combatant targets by subnational groups or clandestine agents
The Weather Underground was a subnational group; exploding bombs is an act of violence; government offices are non-combatant targets (the Weather Underground also bombed banks); and the use of violence had the political goal of ending the Vietnam War. "Screaming response" or no, this was terrorism.
Under current law, Ayers was a terrorist. This definition is not idiosyncratic; similar definitions can be found in the laws of foreign countries and in international treaties. Ayers seems to think he ought to be excused for violence because his motives were good, but that is the excuse that terrorists always offer—that their political goals justify their use of violence—and naturally the legal definition could not permit such a defense without subverting itself, or turning every terrorism trial into a debate about whether the political ends of the defendants are "good" or "bad" from a moral or political perspective.
Though Ayers is right that the he was a sideshow to the campaign, the term "unrepentant terrorist" seems accurate. Worse terms would be even more accurate.
The op-ed is written carefully; one detects the touch of a lawyer or perhaps an author with lawyerly instincts. Ayers says that he never killed or injured anyone and that he co-founded the Weather Underground in 1970, which "went on to take responsibility for placing several small bombs in empty offices." The natural question that arises is whether the Weather Underground actually did more than what it took responsibility for, and whether Ayers, as its co-founder, is responsible for those unnamed acts, or other acts that occurred prior to the founding of the Weather Underground in 1970. Anyone with even casual knowledge of the days of rage and the other antics of the Weathermen (the term used prior to the founding of the Weather Underground in 1970), and the various disputes involving what the Weather Underground did and did not actually do (as opposed to what it "took responsibility for"), might wonder what Ayers is not telling us, and whether Ayers considers himself responsible for the many injuries and deaths (of his own "comrades" who accidently blew themselves up in a Greenwich Village townhouse prior to the founding of the Weather Underground) even if he did not inflict them with his own hands. Ayres did not first enter the scene when he co-founded the Weather Underground in 1970, as uncareful readers might surmise.
The op-ed is a stupid piece of work; what it says about Ayers I leave to the reader.