UTC and Raytheon announced an all-stock merger earlier this month. The deal, which the two companies called a "merger of equals," would bring together a booming aerospace company with a giant government defense contractor.
It is expected to close in the first half of 2020.
However, the proposal has raised questions among regulators and shareholders about the economic benefits and costs of large mergers.
"If you think about the regulatory landscape, which is the first question in terms of the timing, there is zero overlap," Hayes told CNBC's Phil LeBeau at the Paris Air Show on Monday.
"From a regulatory standpoint, we think nine months at the outsight to get this done. Ten countries, it does not require Chinese approval, so we think we have got a pretty clear path," Hayes said.
Hedge fund mogul and activist investor Bill Ackman has said the proposed UTC-Raytheon merger makes "no sense. "
Ackman, whose Pershing Square Capital Management owned 5.8 million UTC shares at the end of the first quarter, said in a letter addressed to Hayes that the merger would be ill-advised.
Dan Loeb's Third Point is also reportedly thought to be opposed to the deal.
When asked how he would respond to such criticism, Hayes replied: "We have talked to a lot of investors, including Bill and including Dan, and I would say they have both been respectful as we have laid out the rationale."
"This is simply giving us scale from a technology standpoint to do things that we could not possibly do before, whether it's advanced analytics, whether it's AI, autonomy in the cockpit, cyber protection for aerospace systems. … It is phenomenal the opportunities we have."
President Donald Trump told CNBC last week that he was a "little concerned" the proposed deal could harm competition and make it more difficult for the U.S. government to negotiate defense contracts.
Raytheon and UTC have since dismissed concerns about a possible reduction in competition, saying they have very little overlap that would generally spark concern among anti-trust regulators.
"As far as objections from shareholders, I think, again, the more we talk about technology, the more they see the benefits, the easier this is going to be to convince people," Hayes said.
The new company, to be called Raytheon Technologies, would become the second-largest aerospace and defense company in the U.S., after Boeing, with an estimated $74 billion in sales.
Raytheon International CEO John Harris told CNBC on Monday he could not remember a time when the two companies were competing during the past 35 years.
Harris also said he did not see the deal as an indication of more mergers in the aerospace industry.
"As we have talked to the customers, as we have talked to the Department of Defense, they have been very intrigued by the opportunities that the merger gives," UTC's Hayes said.
"Obviously, investors were a little bit surprised. I tell people, look, this is the final piece of the puzzle for UTC in terms of our journey from a conglomerate multi-industry to a focused A&D company," he said, referring to aerospace and defense.
"I was joking with the folks at Raytheon that they have been on our radar for a long time. Of course, they are the preeminent company in the world," he added.