  The dynamical picture of a quark-antiquark interaction in light mesons, which
provides linearity of radial and orbital Regge trajectories (RT), is studied
with the use of the relativistic string Hamiltonian with flattened confining
potential and taking into account the self-energy and string corrections. Due
to the flattening effect both slopes, $\beta_n$ of the radial and $\beta_l$ of
the orbital RT, decrease by $\sim 30\%$ with the value of
$\beta_n=1.30(5)$~GeV$^2$ being larger than $ \beta_l=0.95(5)$~GeV. The
self-energy correction provides the linearity of RT and remains important up to
very high excitations; the string correction decreases the slope of the orbital
RT, while the intercept $\beta_0=0.51(1)~ $GeV$^2$ is equal to the squared
centroid mass of $\rho(1S)$. If the universal gluon-exchanged potential without
fitting parameters and screening function, as in heavy quarkonia, is taken,
then the slope of the radial RT decreases, $\beta_n=1.15(8)$~GeV$^2$, and its
value coincides with the slope of the orbital RT, $\beta_l=1.08(8)$~GeV$^2$
within theoretical errors, producing the universal RT.
