"We are in constant contact with North Korea", Trump said on Friday.
North Korea has long sought the removal of those troops as one of its condition for denuclearization.
According to its website, North Korea's state-owned carrier Air Koryo flies to cities in Russian Federation and China, two countries that maintain diplomatic relations with Pyongyang.
Trump predicted "very good things" from the meeting, which will be the first between a U.S. president and a North Korean leader since the end of the Korean War.
The meeting between North Korean leader Kim Jong Un and South Korean President Moon Jae-in was short of specifics and failed to clear up the question of whether Pyongyang is really willing to give up nuclear missiles that now threaten the United States.
US National Security Advisor John Bolton earlier denied as "utter nonsense" a New York Times report saying Trump had asked the Pentagon for options to prepare for drawing down the 28,500-strong US force.
Preparations for the Trump-Kim meeting have gathered further momentum since the Korean summit. It remains unclear if Kim has relaxed that demand as he turns to diplomacy with adversaries after a year of escalating tensions. But I think a lot of great things will happen.
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In Panmunjom, Kim had said he found it a "painful wrench" to see clocks at the summit venue showing different times for the two neighbours, KCNA reported earlier.
"Now, I have to tell you, at some point into the future, I would like to save the money".
The clocks in North Korea have been adjusted 30 minutes ahead and now correspond to South Korean time, the Korean Central News Agency reported on Friday.
"The trip is being scheduled", Trump said.
During his presidential campaign, Trump complained that South Korea does not do enough to financially support the American military commitment. The two leaders signed a peace accord and officially ended the Korean War, which started in 1950.
The Trump administration is also engaged in efforts to secure the release of three Americans imprisoned in North Korea.
Trump hinted that the release of Kim Dong Chul, Kim Hak Song and Tony Kim was in the offing, but again was sparing on the details.