Travel companies and airlines increased their offerings to Spain over the last couple of years as demand shifted away from Turkey and Egypt on security grounds.
The resulting competition put pressure on prices and was one of the reasons behind the demise of airlines Air Berlin and Monarch last year.
TUI said bookings to Turkey from Germany for this summer were up by around 50 percent, while Egypt was also up.
"Both destinations, which are very big destinations, are back," CEO Fritz Joussen told journalists on Tuesday after the group reported first quarter results.
Rival Thomas Cook last week said that recovering demand for trips to Turkey would help offset the impact on its business of rising costs in Spain.
"Turkey and Europe will make 2018 a strong year for Thomas Cook and TUI," Bernstein analysts said on Monday as they upgraded Thomas Cook to "market-perform".