The presidential candidate was left shaken after the man attempted to jump on stage at Dayton International Airport in Ohio.
But Secret Service members quickly pounced on the intruder.
Speaking in Kansas City on Sunday, the property magnate said: "I was ready. I don't know if I would have done well but I would have been out there fighting, folks.”
He said the man "was looking to do harm”.
The shocking incident came after a Trump rally in Chicago on Friday descended into chaos with protesters brawling with supporters of the Republican hopeful.
Trump accused followers of Democratic candidate Bernie Sanders for causing the clashes, branding the left-wing Vermont senator “our communist friend”.
But the 74 year-old strongly hit back, saying: “As is the case virtually every day, Donald Trump is showing the American people that he is a pathological liar.
The scenes in Chicago followed a series of recent incidents of violence at Trump rallies in which protesters and journalists have been punched, tackled and hustled out of venues.
Last week, a white Trump supporter punched a black protester in the face at a rally in North Carolina.
Despite the spate of violence, millionaire Trump has vowed to continue with a rally in Cincinnati today.
“Obviously, while I appreciate that we had supporters at Trump's rally in Chicago, our campaign did not organise the protests.”
And Democratic frontrunner Hillary Clinton slammed Mr Trump for his “ugly, divisive rhetoric”, Express reported.
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