  We report the discovery of the planets WASP-20b and WASP-28b along with
measurements of their sky-projected orbital obliquities. WASP-20b is an
inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R_{\rm Jup}$) in a
4.9-day, near-aligned ($\lambda = 8.1 \pm 3.6^\circ$) orbit around CD-24 102
($V$=10.7; F9). WASP-28b is an inflated, Jupiter-mass planet (0.91 $M_{\rm
Jup}$; 1.21 $R_{\rm Jup}$) in a 3.4-day, near-aligned ($\lambda = 8 \pm
18^\circ$) orbit around a $V$=12, F8 star. As intermediate-mass planets in
short orbits around aged, cool stars ($7^{+2}_{-1}$ Gyr for WASP-20 and
$5^{+3}_{-2}$ Gyr for WASP-28; both with $T_{\rm eff}$ < 6250 K), their orbital
alignment is consistent with the hypothesis that close-in giant planets are
scattered into eccentric orbits with random alignments, which are then
circularised and aligned with their stars' spins via tidal dissipation.
