Thanks for these brainstretchers, Jolan.
You always manage to puzzle and delight.
Here is my stab at today's clues.
1. Flier longing to return after sentimentality shown by girlfriend (10)- GOONEYBIRD? – (Goo is sentimentality. Yen is longing. Reverse this and add “bird” old word for girlfriend to give Goo ney bird, a flier) [There was something familiar about this.... ]
2. Unreliable first lieutenant loses fleet on the way (2,8)- IN TRANSITU? (Unreliable is the anagrind for a subtractive anagram of “first lieutenant” which loses “fleet” to give “in transitu"- on the way)
3. Irrelevant pickpocket works best here (6,3,4)- BESIDE THE MARK? (Mark is a pickpocket’s word for the intended victim, so she or he would work best there. “Beside the mark” means irrelevant.)
4. They may gasp in awe at her withdrawal towards the windward side (1-7)- A WEATHER? (Hidden in clue, nautical phrase meaning “towards the windward side”)
5. Three awful cyberterrorist platitudes, each one following the first for emotional fervour (4)- HWYL? ( The second letters of each of the first four words are “each one following the first”. This spells out hwyl- an emotional fervour )
Enjoy your Easter break.
Thanks again.
AB