I saw the following 42 aircraft at Houston (IAH) on Saturday, March 13, 2021:
4X-EDF 787-9 Dreamliner El Al Israel Airlines
N110SY ERJ-175-LR (ERJ-170-200 LR) United Express
N12163 ERJ-145-XR ExpressJet Airlines
N14148 ERJ-145-XR CommutAir
N16147 ERJ-145-XR CommutAir
N17138 ERJ-145-XR Trans States Airlines
N17146 ERJ-145-XR Trans States Airlines
N17529 737-9 MAX United Airlines
N19136 757-224(WL) United Airlines
N211FJ A320-214 Frontier Airlines
N27246 737-824(WL) United Airlines
N33203 737-824(WL) United Airlines
N33284 737-824(WL) United Airlines
N358JB ERJ-190-AR (ERJ-190-100 IGW) JetBlue Airways
N37513 DC-6 United Airlines
N37518 737-9 MAX United Airlines
N458UA A320-232 United Airlines
N603UX ERJ-175-LL (ERJ-170-200 LL) United Express
N620UX ERJ-175-LL (ERJ-170-200 LL) United Express
N643UA 767-322(ER)(WL) United Airlines
N66828 737-924(ER)(WL) United Airlines
N69818 737-924(ER)(WL) United Airlines
N76526 737-824(WL) United Airlines
N77430 737-924(ER)(WL) United Airlines
N77431 737-924(ER)(WL) United Airlines
N775XF A319-111 American Airlines
N795SK CRJ-702-ER United Express
N82338 ERJ-175-LR (ERJ-170-200 LR) United Express
N833UA A319-131 United Airlines
N835UA A319-131 United Airlines
N85340 ERJ-175-LR (ERJ-170-200 LR) United Express
N85352 ERJ-175-LR (ERJ-170-200 LR) United Express
N85354 ERJ-175-LR (ERJ-170-200 LR) United Express
N85358 ERJ-175-LR (ERJ-170-200 LR) United Express
N86324 ERJ-175-LR (ERJ-170-200 LR) United Express
N86350 ERJ-175-LR (ERJ-170-200 LR) United Express
N87306 ERJ-175-LR (ERJ-170-200 LR) United Express
N87339 ERJ-175-LR (ERJ-170-200 LR) United Express
N87512 737-824(WL) United Airlines
N88359 ERJ-175-LR (ERJ-170-200 LR) United Express
N89313 ERJ-175-LR (ERJ-170-200 LR) United Express
N89342 ERJ-175-LR (ERJ-170-200 LR) United Express