Edit boxes are single lined and single lined edit controls cannot have multi-lined text. So you can't add a row to an edit box. Instead, you could add another row of edit boxes. Or you could replace the edit boxes with tables and then control the number of rows in the table. The table method is probably cleanest and most efficient. Your table could have 4 columns with headers [latitude, longitude, altitiude, airspeed], and you could add and subtract rows as needed.
Here's some background info to tables in app designer
