It is possible that the text that says "Flight Reservation" comes up very quickly, but the code that runs when you activate the Flight Reservation window is still loading.
Whenever you wait for a control, try to wait for the exact property of the control that matches what you want to do in your next line of code.
In this case, you want to activate that window, so you need that window to be enabled. So, wait for the enabled property instead of the text property.
That usually works, but not always.
One other thing you can do is set your sync timeout right before you use .sync on this window, then set it back to the original value right after. You do this using the QuickTest Automation object (there's a ton of info on this feature in the QTP Help documentation) but here's a sample that I copy/pasted from the Help document:
Set qtApp = CreateObject("QuickTest.Application") ' Create the Application object
' set run settings for the test
Set qtTest = qtApp.Test
qtTest.ObjectSyncTimeOut = 20
"The last 10% of any software project will take 90% of the budgeted time. The first 90% will take the other 90%"