Fifth Wheel solution
by Kegler

The overloaded squares say TWO IS COMPANY, THREE'S A CROWD, in pairs and trios.

Fifth Wheel solution grid

Across
1M.O. + HAWKS
5CHIC (AN) + O
9NITWIT (hidden)
10BREAK POINT (PART ON BIKE anag)
11SCATTER + ED
12COM(B)ING
14STREET PARTY (ARREST PETTY anag)
16AG + ON + Y (GA rev)
18THe + dRUMS
20S(PEAK)ING + O + F
24LESSEN ("LESSON" hom)
25WAR + RANT + EES (SEE rev)
28DIACRITICAL (ACIDIC TRAIL anag)
29B(LOWDR)Y (WORLD anag)
30MODE + LED
31D + ESERVE (REEVES anag)
Down
1MENISCUS (hidden)
2H + OT(WA)TER
3WITHERED (hidden)
4SA(B)LE
5COED (CODE anag)
6IR(K)S + O + ME
7A(VO)IDING
8ON + TO + GErmaNY
13ETNA (ANTE rev)
15PA(M)PA
17DISROBES (SOS BRIDE anag)
18T(H,R)ALL + DOM
19MAS + SACRED (SAM rev)
21GUNPOWDER (UP RED GOWN anag)
22FREESTYLE ("FREEZE TILE" hom)
23RE(N)TAL (LATER rev)
26A + ILED (DELI rev)
27ICED (hidden)