Yes, as long as the travel was booked through your portal, you can pull up a list of who is travelling where and on what dates. The system already holds the trip dates, the destination city, the flight or train details and the hotel for every confirmed booking, so it can be searched the other way round, by place and date instead of by traveller name. That gives you a view of everyone from that company who is in a particular city or country on a given day, along with the contact details held on their traveller profile.
In practice most agencies use this in two ways. One is a planned check, where you look a week ahead to see who is going where, which is also useful for the company's own HR and security people. The other is the urgent check, when there is a strike, a storm or unrest somewhere and the client calls you asking who they need to worry about. Because the information comes from the bookings themselves, you can usually produce that list in a couple of minutes and send it across, or message the affected travellers directly if your plan includes email and messaging.
There are honest limits. The system only knows about trips that went through you. If an employee books a hotel directly or buys a flight on an airline site, it will not appear unless someone enters it by hand. Live information such as whether a flight has actually departed depends on what the airline or supplier API sends back, and not every supplier sends it, so treat the list as a record of where people are meant to be rather than a live tracker.
Before you promise this to a corporate client, agree with them that all staff travel is booked through your portal, and ask us which supplier feeds on your plan return flight status updates.