I had the same problem with thunar too, but it is fixed for now.
Thunar uses the gtk2 library, so it should be easy enough to change hotkeys using the standard method. From the archwiki
Enabling Customizable Keyboard Shortcuts
You can customize your GTK+ applications' keyboard shortcuts (those are called accelerators in GTK+ terminology) by hovering your mouse over a menu item and pressing your desired key combination.
However, this feature is disabled by default. So to enable it, your ~/.gtkrc-2.0 or ~/.gtkrc-2.0.mine files should contain this line
At this point, I was able to change my hotkeys using the above method. But then for some unknown reason, they would always change back to default sometime later. So to effect a more permanent change in my hotkeys, I looked at the ~/.config/Thunar/accels.scm file. By default it looks like this
$ head -6 ~/.config/Thunar/accels.scm
; Thunar GtkAccelMap rc-file -*- scheme -*-
; this file is an automated accelerator map dump
; (gtk_accel_path "<Actions>/ThunarLauncher/sendto-desktop" "")
; (gtk_accel_path "<Actions>/ThunarStandardView/create-folder" "<Primary><Shift>n")
; (gtk_accel_path "<Actions>/ThunarWindow/view-side-pane-menu" "")
All the lines are preceded with a semi-colon, so they are comment lines that do nothing. So to add my hotkeys, I added some uncommented lines
(gtk_accel_path "<Actions>/ThunarWindow/back" "<Primary>Left")
(gtk_accel_path "<Actions>/ThunarWindow/open-parent" "<Primary>Up")
which in my case equate to setting the hotkey for Go-->Back to Ctrl-Left, and Go-->Parent to Ctrl-Up. For that file, <Primary> equates to the ctrl key, and <Alt> is the alt-key.
And after all that, my two hotkey changes were permanent. So perhaps you can follow my method and do the same. I am still using thunar-1.2.3, whereas the latest version is 1.6 or greater. So depending on the version, your results may vary.
Happy with ur solution... then tick "yes" and mark as Solved!