  In this work, we study the contributions of the intermediate bottomoniumlike
$Z_b$ states and the bottom meson loops in the heavy quark spin flip
transitions $\Upsilon(4S) \to h_b(1P,2P) \pi^+\pi^-$. Depending on the
constructive or destructive interferences between the $Z_b$-exchange and the
bottom meson loops mechanisms, we predict two possible branching ratios for
each process: BR$_{\Upsilon(4S) \to
h_b(1P)\pi^+\pi^-}\simeq\big(1.2^{+0.8}_{-0.4}\times10^{-6}\big)$ or $\big(
0.5^{+0.5}_{-0.2}\times10^{-6}\big)$, and BR$_{\Upsilon(4S) \to
h_b(2P)\pi^+\pi^-}\simeq \big(7.1^{+1.7}_{-1.1}\times10^{-10}\big)$ or $\big(
2.4^{+0.2}_{-0.1}\times10^{-10}\big)$. The bottom meson loops contribution is
found to be much larger than the $Z_b$-exchange contribution in the
$\Upsilon(4S) \to h_b(1P) \pi\pi$ transitions, while it can not produce decay
rates comparable to the heavy quark spin conserved $\Upsilon(4S) \to
\Upsilon(1S,2S) \pi\pi$ processes. We also predict the branch fractions of
$\psi(3S,4S) \to h_c(1P)\pi^+\pi^-$ contributed from the charm meson loops.
