if you are using mavros 0.12 use the branch mavros0.12
git checkout mavros0.12
mkdir -p takeoff_land_ws/src && cd takeoff_land_ws/src
git clone https://github.com/erlerobot/ros_erle_takeoff_land
cd ..
catkin_make_isolated --pkg ros_erle_takeoff_land
source takeoff_land_ws/devel_isolated/ros_erle_takeoff_land/setup.bash
rosrun ros_erle_takeoff_land ros_erle_takeoff_land