Of the 20thc Flute concertos, I have grown to like that by Carl Neilsen, also the Fugal concerto (flute & oboe) by Gustav Holst.
Of the romantics, I particularly like the Reinecke & Chaminade.
But my favourites are those of J.Haydn & W.Mozart, who, for me at least, capture the beauty of the flute better than anyone else. Bellini & Donizetti also wrote flute concertos, as far as I know.
A recently released disc , and a work, which I haven't yet heard, is a Symphony Concerto for Flute & orchestra by Hendrik Waelput (1845-85), completely unknown to me. Also on the disc are the Concerto symphonique for Flute & orchestra by Benoit & the Fetis concerto. Has anyone heard the Waelput work ?
I am not a great fan of Trumpet(or Trombone) concertos. I find the blaring sounds, particularly in the hands of some players, an assault on the ear. But having said that, I love the E flat concerto of Haydn, & those by Mozart, Telemann & Hummel are good to listen to occasionaly.
Also the Bach Brandenburg concertos (no2), are above criticism, & although the instrument (trumpet) was different from the modern instrument, the timbre is the same, but I am in the wrong century !
Two virtuoso Flute concertos have been written by New Zealand composers Alan Ritchie (b1960), and Chloe Moon (b1952). Both are entertaining neo classical works. Ritchie has also recently written a Double Concerto for Bass Clarinet, Cello & orchestra.
Marcus.